WO2009006850A1

WO2009006850A1 - Hollow fiber membrane or capillary membrane filter and water filtration method using such a filter

Info

Publication number: WO2009006850A1
Application number: PCT/CN2008/071607
Authority: WO
Inventors: Guangzhen Meng; Lizhou Huang
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-07-11
Filing date: 2008-07-10
Publication date: 2009-01-15
Anticipated expiration: 2010-01-11

Abstract

A method of filtering water and a membrane filter (100). The filter (100) includes a collecting chamber (120) and a plurality of membranes (110). Each membrane (110) includes a sealed free end (111), a tube cavity, and an open potted end (112). The open potted end (112) is in fluid communication with the collecting chamber (120). The sealed free end (111) can move laterally substantially freely, causing solids on external walls of the plurality of membranes (110) to fall by gravitational force to a bottom portion of a reservoir, and to be drained out of the system. Unfiltered water can be directed toward the open potted ends (112) to scrub the membranes (110) with unfiltered water without entangling the membranes (110).

Description

HOLLOW FIBER MEMBRANE OR CAPILLARY MEMBRANE FILTER AND WATER FILTRATION METHOD USING SUCH A FILTER

BACKGROUND

Known techniques use hollow fiber membranes or capillary membranes to form pressurized or submerged membrane filters. Submerged membrane filters are often used to filter liquid with a high impurity content. Submerged membrane filters generally reduce the sedimentation of solid impurities on the membrane surfaces and the pollution caused to the membrane surfaces by cascading air upward to the liquid surrounding the membranes. A special application of a submerged membrane filter is the filtration of the aqueous liquid in the biochemical reactor of a waste water treatment system. The technology of this combination of bio-reactor and membrane filter assembly is known as a membrane bio-reactor (MBR). In addition, Chinese Patent Application No. 200610002387X combines a bio-film bio-reactor with a membrane filter, and this technology is called a membrane enhanced bio-reactor (MEBR).

Submerged membrane filters are generally divided into two types - curtain-type filters and pillar-type filters. One of the common features of these filters is that both ends of the hollow fiber or capillary membranes are potted together. For example, the top ends of the membranes are potted together and the bottom ends of the membranes are potted together. However, the air scouring effects near the potted ends are relatively poor, and solids often deposit near the potted ends of the membranes and reduce the effectiveness of the filter.

To resolve this problem, US Patent Application No. 2004/0035779A1 discloses a vertically placed straw-type membrane filter with the bottom of the hollow fiber membranes or capillary membranes and the water collecting chamber at the bottom being cast together. However, descending solids have a tendency to deposit at the bottoms of the hollow fiber membranes or capillary membranes gradually polluting the membranes upward from the bottom ends of the membranes.

One of the common features of the abovementioned filters is that the hollow fiber membranes or capillary membranes are submerged in the filtered liquid in an open manner. Although the liquid near the membrane surface can be stirred by means of cascading air, the kinetic energy of liquid flow on the membrane surfaces is relatively low, and this results in a higher concentration of pollutants on the membrane surfaces, contamination of the membranes, and a reduction of filtration flux per unit area of the membranes.

To enhance liquid flow on the membrane surfaces, US Patent No. 7,179,370 discloses adding plates around an assembly of membrane filters to form a membrane case. The membrane case formed by the plates has an open top and an open bottom. Cascading air at the bottom ends of the membranes creates an air-lift effect that causes the air-liquid mixture to flow upward inside the membrane case and to flow downward outside the membrane case in order to achieve liquid scouring of the membrane surfaces. Similarly, Chinese Patent Application No. 200610113851.2 discloses a device and a method for sewage treatment using a double-cylinder air lift membrane bio-reactor. Both US Patent No. 7,179,370 B2 and Chinese Patent Application No. 200610113851.2 disclose pillar-type membrane filters with potted bottom ends. However, the air-liquid flow generated by the air-lift effect is not able to scour the bottom portion of the membrane fibers or capillaries, and this results in membrane fouling that gradually develops upward.

SUMMARY OF THE INVENTION

Some embodiments of the invention provide a membrane filter including a collecting chamber and a plurality of membranes. Each of the membranes includes a sealed free end, a tube cavity, and an open potted end. The open potted end is in fluid communication with the collecting chamber. The sealed free end is allowed to move laterally substantially freely, causing solids on external walls of the membranes to fall by gravitational force to a bottom portion of a reservoir, and to be drained out of the system. Some embodiments of the invention provide a shell around the membranes. Unfiltered water can be directed to flow around the membranes so that the surface of the membrane is scrubbed by water. Some embodiments of the invention include an enclosure around the membranes that makes pressurized filtration possible.

Embodiments of the invention provide a method of filtering water. The method can include suspending membranes in unfiltered water and allowing sealed free ends of the membranes to move laterally substantially freely. The method can also include directing unfiltered water flow toward the open potted ends and around the membranes to scrub the membranes. In some embodiments, the method can include a pressurized filtration operation. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a front elevation of a first type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 2 is a longitudinal cross-section view of the first type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention shown in Figure 1.

Figure 3 is a front elevation of a second type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 4 is a longitudinal cross-section view of the second type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention shown in Figure 3.

Figure 5 is front elevation of a third type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 6 is a lateral cross-section view of the third type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention shown in Figure 5.

Figure 7 is a longitudinal cross-section view of the third type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention shown in Figure 5.

Figure 8 is a front elevation view of a forth type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 9 is a longitudinal cross-section view of the forth type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 10 is a front elevation view of the fifth type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 11 is a longitudinal cross-section view of the fifth type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 12 is the front elevation view the sixth type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 13 is the longitudinal cross-sectional view of the sixth type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention. Figure 14 is the front elevation view the seventh type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 15 is the longitudinal cross-sectional view of the seventh type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 16 is the longitudinal cross-sectional view of the eighth type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

Figure 17 is the longitudinal cross-sectional view of the ninth type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention.

DETAILED DESCRIPTION

Referring to Figure 1 and Figure 2, the first type of the weeping willow type hollow fiber membrane or capillary membrane filter 100 of this invention includes a plurality of membranes 110 and a collecting chamber 120. As used herein and in the appended claims, the term "membranes" refers to either hollow fiber membranes, capillary membranes, or other suitable membranes. In some embodiments, the membranes 110 are internally-supported, multi-bore membranes as disclosed in Chinese Patent Application No. 200720154983.x entitled "Internally Supported Capillary Membrane" filed on July 23, 2007, the entire contents of which is herein incorporated by reference. In some embodiments, each membrane 110 can include an individually sealed free end (such as its bottom end 111), an open potted end (such as its top end 112), and a tube cavity inside the membrane 110. The top ends 112 of the membranes 110 are potted together by potting resin 140 with the collecting chamber 120. The tube cavity of each membrane 110 is connected to the internal cavity of the collecting chamber 120.

Using the internally-supported, multi-bore membranes, water can be directed toward the open potted ends or top ends 112 of the membranes 110 without entangling the membranes 110. Unfiltered water can be directed toward the open potted end and then filtered water can be directed through the tube cavity and into the collecting chamber 120 in an outside-in filtration configuration. The collecting chamber 120 has at least one opening 121 in its wall. In some embodiments, the sealed or bottom ends 111 of the membranes 110 face downward and are allowed to swing or move laterally substantially freely. This can cause solids on external walls of the membranes 110 to fall by gravitational force to a bottom portion of the tank or reservoir to be drained out of the system.

In application, the first type of the weeping willow type hollow fiber membrane or capillary membrane filter 100 can be installed in unfiltered liquid or membrane bio-reactor tanks so that the sealed bottom ends 111 of each hollow fiber membrane or capillary membrane 110 are facing downward, while the collecting chamber 120 is facing upward, as shown in Figure 1 and Figure 2. In the working process of the weeping willow type hollow fiber membrane or capillary membrane filter 100, the internal cavity of the collecting chamber 120 is subjected to negative pressure if necessary, and the treated water enters the tube cavity through the tube walls of the hollow fiber membranes or capillary membranes 110 under the gratitude force or the applied negative pressure in the internal cavity of the collecting chamber 120 before delivered further through the tube opening 121. Solid particles or active sludge contained in the unfiltered water or contained in the unfiltered water of the membrane bio-reactor are retained outside the hollow fiber membranes or capillary membranes 110, and the solids or active sludge particles filtered by the membranes descent to the bottom of the tank under gravitational force, and are drained from the bottom of the tank via a drain or pipeline.

In some embodiments, air can be released from a gasification device 130 positioned beneath the bottom ends 111 of the hollow fiber membranes or capillary membranes 110, forming small air pillars and small air bubbles in the waste water that move up to the unfiltered water surface. The hollow fiber membranes or capillary membranes 110 located above the top of the gasification device 130 can swing substantially ceaselessly under scouring caused by the small air pillars and small air bubbles, causing the solids and active sludge sticking on the external walls of the hollow fiber membranes or capillary membranes 110 to fall off the walls to the bottom of the unfiltered water tank and to be drained from the bottom of the unfiltered water tank via a drain or pipeline.

The basic configuration of the second type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention as shown in Figure 3 and Figure 4 is similar to that of the first type of weeping willow type hollow fiber membrane or capillary membrane filter of this invention as shown in Figure 1 and Figure 2. The identical parts are marked with same numerals and will not be repetitively described.

The basic configurations of the second type of weeping willow type hollow fiber membrane or capillary membrane filter 200 of this invention as shown in Figure 3 to Figure 4 distinguish themselves from the basic configuration of the first type of weeping willow type hollow fiber membrane or capillary membrane filter 100 in such a way that it includes an additional cylindrical porous shell or net shell 150. The cylindrical porous shell or net shell 150 is installed on a surface of the collecting chamber 120 with a hoop ring 160 or bolts 170. In this manner, the cylindrical porous shell or net shell 150 can restrict to a certain range the substantially ceaseless swing of some portions (such as the bottom and middle portions) of the hollow fiber membranes or capillary membranes 110. In some embodiments, the lateral movement of the membranes 110 adjacent to the gasification device 130 can be restricted in order to help prevent the hollow fiber membranes or capillary membranes 110 from being damaged.

The basic configuration of the third type of weeping willow type hollow fiber membrane or capillary membrane filter 300 of this invention as shown in Figure 5 to Figure 7 is similar to that of the first type of weeping willow type hollow fiber membrane or capillary membrane filter 100 of this invention as shown in Figure 1 and Figure 2, and is similar to that of the second type of weeping willow type hollow fiber membrane or capillary membrane filter 200 of this invention as shown in Figure 3 and Figure 4. The identical parts are marked with same numerals and will not be repetitively described.

The basic configurations of the third type of weeping willow type hollow fiber membrane or capillary membrane filter 300 of this invention as shown in Figure 5 to Figure 7 distinguish themselves from the basic configuration of the first and the second types of weeping willow type hollow fiber membrane or capillary membrane filter 100 and 200 of this invention in such a way that the central cascading air tube 310 is installed along a longitudinal central axis of the collecting chamber 120. The central cascading air tube 310 has an opening on its top and protrudes from a sealed top wall of the collecting chamber 120. The bottom of the central cascading air tube 310 is sealed and protrudes downward from the bottom ends 111 of the hollow fiber membranes or capillary membranes 110. The bottom portion of the tube wall is provided with a number of holes 311 (for example, as a substitute to the gasification device 130 of the first and the second types of weeping willow type hollow fiber membrane or capillary membrane filter 100 and 200 of this invention). The top portion of the external wall of the central cascading air tube 310, the internal wall of the collection chamber 120, and the external walls of the membranes 110 are potted together by sealing resin 140. The portion of the external wall of the central cascading air tube 310 that is in contact with the sealing resin 140 can together form a sealed connection. It can be advantageous to use the central cascading air tube 310 instead of the gasification device 130, because the central cascading air tube 310 provides a rigid support for the plurality of hollow fiber membranes or capillary membranes 110; and because the central cascading air tube 310, the collecting chamber 120 and the plurality of hollow fiber membranes or capillary membranes 110 form an integral weeping willow type hollow membrane fiber or capillary membrane filter 300 that can be easier to install than the combination of a membrane filter and separate gasification device 130.

In some embodiments, membrane filters in the configurations of the first to the third types of the weeping willow type hollow fiber membrane or capillary membrane filter 100, 200 and 300 of this invention help ensure that substantially all the surfaces of the membranes in a submerged membrane filter are scrubbed by provided air through a gasification device and by having the bottom ends of the membrane capillaries or hollow-fibers free from each other in order to allow air to reach substantially all the surfaces of the membrane capillaries or hollow-fibers.

The basic configuration of the fourth type of weeping willow type hollow fiber membrane or capillary membrane filter 400 of this invention as shown in Figure 8 to Figure 9 is similar to that of the first type of weeping willow type hollow fiber membrane or capillary membrane filter 100 of this invention as shown in Figure 1 and Figure 2. The identical parts are marked with same numerals and will not be repetitively described. The basic configurations of the fourth type of weeping willow type hollow fiber membrane or capillary membrane filter 400 of this invention as shown in Figure 8 to Figure 9 distinguish themselves from the basic configuration of the first type of weeping willow type hollow fiber membrane or capillary membrane filter 100 in such a way that also it includes a shell 150 which is installed on the surface of the collecting chamber 120 with a hoop ring 160 or a bolts 170. In this manner, the shell 150 restricts to a certain range the substantially ceaseless swing of some portions (such as the bottom and middle portions) of the hollow fiber membranes or capillary membranes 110 located above the top portion of the gasification device 130 in order to help prevent the hollow fiber membrane or capillary membrane 110 from being damaged. At the same time, the air-lift effect taking place within the shell 150 produces liquid flow on the membrane surfaces. The shell 150 is provided with water outlets 180 on its upper portion. The air-lifted water flow can flow in from the space between the bottom portion of the shell 150 and the gasification device 130. As a result, the specific gravity of an air-liquid mixture inside the shell 150 can be less than outside the shell 150. In one embodiment, the bottom of the shell 150 is provided with at least one water inlet 190 to facilitate the formation of air-lift circulatory flow.

The basic configuration of the fifth type of the weeping willow type hollow fiber membrane or capillary membrane filter 500 of this invention as shown in Figure 10 and Figure 11 is similar to that of the forth type of the weeping willow type hollow fiber membrane or capillary membrane filter 400 of this invention as shown in Figure 8 and Figure 9. The identical parts are marked with same numerals and will not be repetitively described.

The basic configuration of the fifth type of the weeping willow type hollow fiber membrane or capillary membrane filter 500 of this invention as shown in Figure 10 and Figure 11 distinguishes itself from the basic configuration of the fourth type of the weeping willow type hollow fiber membrane or capillary membrane filter 400 of this invention as shown in Figure 8 and Figure 9 in such a way that the central cascading air tube 310 is installed along the longitudinal central axis of the collecting chamber 120 and the central cascading air tube 310 has an opening on its top and protrudes from the sealed top wall of the collecting chamber 120. The bottom of the central cascading air tube 310 is sealed and protruded downward from the bottom ends 111 of the hollow fiber membranes or capillary membranes 110, and the bottom portion of the tube wall includes a plurality of holes 311. The central tube 310 and the holes 311 serve as a substitute to the gasification device 130 positioned under the bottom ends 111 of the hollow fiber membranes or capillary membranes 110 of the fourth type of the weeping willow type hollow fiber membrane or capillary membrane filter of this invention as shown in Figure 8 and Figure 9. The top portion of the external wall of the central cascading air tube 310, the internal wall of the shell 150, and the external walls of the membranes are potted together by sealing resin 140. It can be advantageous to use the central cascading air tube 310 instead of the gasification device 130, because the central cascading air tube 310 provides a rigid support for the hollow fiber membranes or capillary membranes 110 and because the central cascading air tube 310, the collecting chamber 120, and the plurality of hollow fiber membranes or capillary membranes 110 form an integral weeping willow type hollow membrane fiber or capillary membrane filter 300 that can be easier to install than the combination of a membrane filter and a separate gasification device 130.

In some embodiments, membrane filters in the configurations of the fourth to the sixth types of the weeping willow type hollow fiber membrane or capillary membrane filter 400 and 500 of this invention help ensure that substantially all the surfaces of the membranes are scrubbed not only by provided air through the gasification device, but also by water current inside the shell 150 created by an air lifting effect.

The basic configuration of the sixth type of weeping willow type hollow fiber membrane or capillary membrane filter 600 of this invention as shown in Figure 12 to Figure 13 is similar to that of the fourth type of weeping willow type hollow fiber membrane or capillary membrane filter 400 of this invention as shown in Figure 8 and Figure 9. The identical parts are marked with same numerals and will not be repetitively described.

The basic configurations of the sixth type of weeping willow type hollow fiber membrane or capillary membrane filter 600 of this invention as shown in Figure 12 to Figure 13 distinguish themselves from the basic configuration of the forth type of weeping willow type hollow fiber membrane or capillary membrane filter 400 of this invention in such a way that the bottom of the shell 150 is enclosed by a feed chamber 410 that includes a water inlet 411 and a gasification device. The top holes in the shell 150 are combined into at least one outlet 122. The collecting chamber 120 and the feed chamber 410 are coupled to the shell 150 by joints or brackets 160. Filtration can be run under pressure for the sixth type of weeping willow type hollow fiber membrane or capillary membrane filter.

The basic configuration of the seventh, the eighth, and the ninth types of weeping willow type hollow fiber membrane or capillary membrane filter 700, 800, and 900 of this invention as shown in Figure 14 to Figure 17 are similar to that of the sixth type of weeping willow type hollow fiber membrane or capillary membrane filter 600 of this invention as shown in Figure 12 and Figure 13. The identical parts are marked with same numerals and will not be repetitively described.

The basic configurations of the seventh type of weeping willow type hollow fiber membrane or capillary membrane filter 700 of this invention as shown in Figure 14 to Figure 15 distinguish themselves from the basic configuration of the sixth type of weeping willow type hollow fiber membrane or capillary membrane filter 600 of this invention in such a way that the outlet 122 in the wall of the sixth type is replaced by a central porous pipe 310 that has a plurality of holes 311 and is installed along a longitudinal central axis of the collecting chamber 120, protrudes from the sealed top wall of the collecting chamber 120, and is held by a securing plate or fixture 134 at the bottom end. The central porous pipe 310 has an opening on its top for the mixture of gas and water to flow out. The central porous pipe 310 provides a better gas and water distribution in the membrane filter.

The basic configurations of the eighth type of weeping willow type hollow fiber membrane or capillary membrane filter 800 of this invention as shown in Figure 16 distinguish themselves from the basic configuration of the seventh type of weeping willow type hollow fiber membrane or capillary membrane filter 700 of this invention in such a way that the central porous pipe is about 10% to about 50% the length of the filter, the bottom of the central porous pipe 310 is sealed, and there are holes 311 in the central porous pipe 310 for gas and water to flow through.

The basic configurations of the ninth type of weeping willow type hollow fiber membrane or capillary membrane filter 900 of this invention as shown in Figure 17 distinguish themselves from the basic configuration of the seventh type of weeping willow type hollow fiber membrane or capillary membrane filter 700 of this invention in such a way that the central porous pipe 310 is about 10% to about 30% the length of the filter, and the bottom of the central porous pipe 310 is left open for gas and water to flow through.

In some embodiments, membrane filters in the configurations of the sixth to ninth types of the weeping willow type hollow fiber membrane or capillary membrane filter 600, 700 , 800 and 900 of this invention help ensure that substantially all the surfaces of the membranes are scrubbed not only by air provided by the gasification device 130, but also by a water current formed from an air lifting effect. It also facilitates a pressurized operation and that in turn makes the membranes much less vulnerable to fouling related to negative lumen pressure of the membranes. Pressurized operation also makes the cleaning of the membranes easier.

Claims

1. A membrane filter comprising:

a collecting chamber; and

a plurality of membranes, each one of the plurality of membranes including a sealed free end, a tube cavity, and an open potted end, the open potted end being in fluid communication with the collecting chamber;

wherein unfiltered water is directed to flow toward the open potted end so that the plurality of membranes are scrubbed by unfiltered water without being entangled.

2. The filter of claim 1 wherein filtered water is directed into the collecting chamber in an outside-in filtration configuration.

3. The filter of claim 1 wherein the collecting chamber includes an internal cavity; wherein the open potted end is sealed in the collecting chamber; and wherein the tube cavity is connected to the internal cavity with the sealed free end facing downward and moving laterally substantially freely.

4. The filter of claim 1 wherein the plurality of membranes swing laterally causing solids on external walls of the plurality membranes to fall by gravitational force to a bottom portion of a reservoir to be drained.

5. The filter of claim 1 wherein the plurality of membranes include at least one internally-supported multi-bore membrane.

6. The filter of claim 1 and further comprising a gasification device positioned beneath the sealed free end of the plurality of membranes.

7. The filter of claim 1 and further comprising a central cascading air tube positioned along a longitudinal central axis of the collecting chamber.

8. The filter of claim 7 wherein the central cascading air tube includes an opening on a top portion that protrudes from a sealed top wall of the collecting chamber for air feeding.

9. The filter of claim 7 wherein a bottom end of the central cascading air tube is sealed and protrudes downward; and wherein a bottom portion of the central cascading air tube includes a plurality of holes.

10. The filter of claim 1 and further comprising a porous shell positioned around at least a portion of the plurality of membranes in order to restrict at least some lateral movement of the plurality of membranes.

11. The filter of claim 10 wherein a top portion of the porous shell is positioned on a surface of the collecting chamber and fixed around outside portions of the plurality of membranes.

12. The filter of claim 1 and further comprising a shell and a gasification device; wherein the shell includes a top portion positioned on a surface of the collecting chamber and fixed around outside portions of the plurality of membranes; wherein the top portion of the shell includes a plurality of holes; and wherein the gasification device is located beneath the sealed free ends of the plurality of membranes.

13. The filter of claim 12 wherein unfiltered water flows upward around the plurality of membranes by an air-lift effect.

14. The filter of claim 1 and further comprising a shell and a central cascading air tube; wherein the shell includes a top portion positioned on a surface of the collecting chamber; wherein the top portion of the shell is fixed around outside portions of the plurality of membranes; wherein the top portion of the shell includes a plurality of holes; wherein the central cascading air tube is positioned along a longitudinal central axis of the collecting chamber and includes an opening that protrudes from a sealed top wall of the collecting chamber for air feeding; wherein a bottom end of the central cascading air tube is sealed and protrudes downward; and wherein a bottom portion of the central cascading air tube includes a plurality of holes.

15. The filter of claim 14 wherein unfiltered water flows upward around the plurality of membranes by an air-lift effect.

16. The filter of claim 1 and further comprising a gasification device and a bottom feed chamber; wherein the gasification device is positioned in the bottom feed chamber; wherein the bottom feed chamber includes a water inlet and a gas inlet; wherein the gasification device is coupled to the gas inlet; wherein the gasification device is located beneath the sealed free ends of the plurality of membranes; and wherein an outlet tube is located on the shell between the collecting chamber and the feed chamber.

17. The filter of claim 16 wherein the filter operates in a pressurized filtration system.

18. The filter of claim 16 and further comprising a pipe positioned along a longitudinal central axis of the collecting chamber; and wherein the pipe includes an opening on a top portion that protrudes from a sealed top wall of the collecting chamber.

19. The filter of claim 18 wherein a bottom portion of the pipe is fixed in a vertical central axis with respect to the bottom feed chamber by a positioning plate.

20. The filter of claim 18 wherein a length of the pipe is about 10% to about 90% of an overall length of the filter.

21. The filter of claim 20 wherein a bottom portion of the pipe is sealed, and wherein the pipe includes a plurality of holes.

22. The filter of claim 20 wherein a bottom portion of the pipe is open.

23. The filter of claim 20 wherein a length of the pipe is about 10% to about 30% of an overall length of the filter and the pipe is positioned adjacent to the collecting chamber.

24. The filter of claim 1 wherein the filter operates in one of a submerged membrane filtration system, a membrane biological reactor, and a membrane enhanced biological reactor.

25. A method of filtering water, the method comprising:

suspending a plurality of membranes in unfiltered water;

allowing sealed free ends of the plurality of membranes to move laterally substantially freely;

directing unfiltered water toward open potted ends of the plurality of membranes so that the plurality of membranes are scrubbed by unfiltered water without entangling the plurality of membranes;

filtering water by passing unfiltered water through the sealed free ends into tube cavities of the plurality of membranes; and

directing filtered water from the tube cavities of the plurality of membranes into a collecting chamber.

26. The method of claim 25 and further comprising allowing the plurality of membranes to swing laterally causing solids on external walls of the plurality of membranes to fall by gravitational force to be drained.

27. The method of claim 25 wherein the plurality of membranes include internally-supported multi-bore membranes.

28. The method of claim 25 and further comprising scouring the plurality of membranes with air.

29. The method of claim 25 and further comprising scouring the plurality of membranes with a current of air and water created by an air-lift effect.

30. The method of claim 25 and further comprising restricting at least some lateral movement of the plurality of membranes.

31. The method of claim 25 and further comprising suspending the plurality of membranes in one of a submerged membrane filtration system, a membrane biological reactor, and a membrane enhanced biological reactor.

32. The method of claim 25 and further comprising pressurizing the unfiltered water in a filtration system.