JP2008238080A - Filtration module and filtration unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filtration module and a filtration unit capable of suppressing the closure of a film and executing efficient filtration over a long period of time by effectively preventing the deposition of suspended matters at the end especially of a hollow fiber membrane. <P>SOLUTION: In the filtration module 1 in which the plurality of hollow fiber membranes 2 disposed in a horizontal direction in raw water W are bundled at the end part 2A and fixed to a fixing part 3, an aeration means 5 is disposed under the end part 2A of the bundled hollow fiber membrane 2. Also, such a filtration module 1 is defined as the filtration module 1 of the bottom stage at least of the filtration unit 11 in which the plurality of filtration modules 1, 14 are piled up while the fixing parts 3 of the filtration modules are arranged in a vertical direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a filtration module that filters raw water using a hollow fiber membrane, and a filtration unit that houses the filtration module in a casing into which raw water is introduced.

Inventors of the present invention, in Patent Documents 1 to 3, accommodate a plurality of filtration modules using such hollow fiber membranes in a casing, and aeration means (aeration pipe) close to the lower side of the filtration module. The filter unit provided with In such a filtration unit, clear raw water from which sludge and the like have been removed to some extent can be introduced into the casing by installing the casing in a water storage tank or the like, so that efficient filtration can be achieved. In particular, in Patent Document 1, by adding activated carbon to raw water introduced into the casing and adding it to the raw water, it is possible to further improve the filtration efficiency by adsorbing organic substances in the raw water by the activated carbon. Are listed.
JP 2006-205074 A JP 2006-205075 A JP 2006-205076 A

  By the way, in the filtration module using the hollow fiber membranes as described in these Patent Documents 1 to 3, the hollow fiber membranes are passed in the lateral direction so that a plurality (multiple) of the hollow fiber membranes form a bundle. Are bundled and immersed in the raw water while being fixed to the fixing portions at both ends of the filtration module. This fixing part is a header part that discharges filtered water filtered by the hollow fiber membrane, and a plurality of end parts in which a plurality of hollow fiber membranes are bundled are arranged in the fixing part in the vertical direction. Thus, a screen-like hollow fiber membrane row is formed, and such a hollow fiber membrane row is further arranged in parallel in a plurality of rows at intervals between the ends to constitute a filtration module.

  However, the air diffuser is disposed between the end portions of the hollow fiber membrane thus passed in the lateral direction. This physical cleaning is performed by swinging the hollow fiber membrane due to aeration from the air diffuser. The hollow fiber membrane swings between the end portions, but the hollow fiber membrane hardly swings at the end portions that are bundled and fixed to the fixing portion. For this reason, turbidity is likely to be deposited on the hollow fiber membrane at this end portion, and the blockage of the membrane is promoted. Thus, when a part of the membrane is blocked, the permeation flux in the other portions that are not blocked Rises and further blockage is promoted, resulting in a decrease in filtration efficiency in a short period of time.

  In addition, in the filtration units described in Patent Documents 1 to 3, when such filtration modules are stacked to form a unit, it is also proposed that a diffuser is provided below the hollow fiber membrane of each stage of the filtration module. However, it is the same that the end of the hollow fiber membrane does not oscillate, and it is difficult to avoid the enhancement of membrane occlusion due to the deposition of turbidity. Furthermore, when activated carbon is supplied and added to the raw water in the casing as described in Patent Document 1, blockage of the membrane is further promoted.

  The present invention has been made under such a background, and can effectively prevent the deposition of turbidity, particularly at the end of the hollow fiber membrane, thereby suppressing the blockage of the membrane for a long period of time. It aims at providing the filtration module which can perform efficient filtration, and the filtration unit provided with this filtration module.

  In order to solve the above-mentioned problems and achieve such an object, the filtration module of the present invention comprises a plurality of hollow fiber membranes that are laterally passed in the raw water and bundled at the end thereof to the fixed portion. It is fixed, and an air diffuser is disposed under the end of the bundled hollow fiber membrane. Further, the filtration unit of the present invention is characterized in that a plurality of filtration modules are stacked with the above-mentioned fixing portions arranged in the vertical direction, and at least the lowermost filtration module is the filtration module of the present invention. To do.

  In the filtration module having such a configuration, since the air diffuser is disposed under the end portion where the plurality of hollow fiber membranes are bundled, the end portion of the hollow fiber membrane fixed to the fixing portion is arranged. Aeration can be performed intensively by this air diffuser. For this reason, it is possible to prevent clogging and prevent the blockage from occurring even at the bundled end portions of the hollow fiber membranes that are not easily rocked by being fixed. Here, it is desirable that this air diffuser continuously diffuses air, so that the raw water around the fixed end of the hollow fiber membrane is always in a fluid state, so that sedimentation of turbidity is more effective. Can be prevented. Further, if this air diffuser is disposed at the lower part of the fixing part, it is possible to aerate air more reliably by concentrating the air bubbles caused by air diffusion along the fixing part at the end of the hollow fiber membrane.

  In particular, in such a filtration module, a hollow fiber membrane array is formed by arranging a plurality of end portions in which a plurality of hollow fiber membranes are bundled in the vertical direction on the fixed portion as described above. In the case where the hollow fiber membrane rows are arranged in parallel in a plurality of rows at intervals between the end portions, aeration means is provided under the end portions as in the present invention for aeration. By carrying out, the air bubbles diffused from this air diffuser rises through the raw water through the part where the hollow fiber membrane ends between adjacent hollow fiber membrane rows are spaced apart, Since air scrubbing is performed on the ends of the hollow fiber membranes arranged in the vertical direction, it is possible to effectively prevent turbidity from being deposited on the ends of the hollow fiber membrane over the entire vertical direction of the fixing portion.

  In the present invention, in order to physically wash the entire hollow fiber membrane, another air diffuser may be disposed below the hollow fiber membrane between the end portions. While cleaning of the entire hollow fiber membrane by the air diffuser is intermittent, especially when the air diffuser by the air diffuser disposed below the end is continuously performed as described above, The amount of air diffused may be less than the amount of air diffused by other air diffusers. By adopting such a configuration, it is possible to reduce the necessary power even if aeration is continuously performed by the aeration means disposed below the end portion. In addition, even when an activated carbon supply means for supplying activated carbon to the raw water is provided to adsorb organic matter or the like, according to the present invention, the activated carbon adheres to the end portion and causes the hollow fiber membrane to be blocked. Can also be prevented.

  On the other hand, in the filtration unit of the present invention, a plurality of filtration modules are united by stacking the above-mentioned fixing parts in the vertical direction, and at least the lowermost filtration module is at the end as described above. Since the filtration module of the present invention is provided with a diffuser means below, even if such a diffuser means is not provided in the upper-stage filtration module, the upper stage is caused by the bubbles generated by the diffuser means rising from below. The end portion of the hollow fiber membrane in the filtration module can be aerated to prevent the deposition of turbidity over the entire filtration module in all stages. Moreover, if such a plurality of filtration modules are accommodated in the casing into which the raw water is introduced, the relatively pure raw water is introduced into the casing by arranging the filtration unit in a water storage tank or the like together with the casing. Therefore, it becomes possible to further prevent turbidity deposition.

  Thus, according to the filtration module and the filtration unit of the present invention, it is possible to effectively prevent the adhering of turbidity at the end of the hollow fiber membrane, which is difficult to swing with the conventional air diffuser. It is possible to prevent clogging of the entire hollow fiber membrane due to the increase in the permeation flux due to the clogging of the end portion as well as the clogging of the end portion. Therefore, it is possible to prevent the filtration efficiency from being reduced in a short period due to such blockage, and to promote efficient filtration over a long period of time.

  1 to 5 show one embodiment of the filtration module of the present invention, and FIGS. 6 and 7 show one embodiment of the filtration unit of the present invention using the filtration module of this embodiment. . As shown in FIGS. 1 and 2, the filtration module 1 of the present embodiment has a plurality (multiple) of hollow fiber membranes 2 passed in the lateral direction (the horizontal direction in FIGS. 1 to 3 and 5). A predetermined number of bundles are bundled at both end portions 2A and fixed to inner surfaces 3A facing each other of a pair of fixing portions 3 forming a flat rectangular box shape in the lateral direction.

  At least one of the pair of fixed portions 3 is a header portion from which filtered water filtered from the raw water by the hollow fiber membrane 2 is discharged, and a filtered water pipe (not shown) is connected to the fixed portion 3. In addition, the hollow portion of the bundled hollow fiber membranes 2 is communicated with the internal space of the fixed portion 3 at the end portion 2A fixed to the fixed portion 3 as the header portion as shown in FIG. It has been. In this embodiment, a hollow fiber MF membrane (pore diameter 0.1 μm) made of hydrophilic polyethylene is used as the hollow fiber membrane 2, but the hollow fiber membrane 2 is not limited.

  Here, in the present embodiment, the hollow fiber membrane 2 in which a predetermined number is bundled as described above has an end portion 2A in the vertical direction (vertical direction in FIGS. 1 and 5) on the inner side surface 3A of the fixing portion 3. 2 and 3 are arranged in series in the direction perpendicular to the drawing), and as shown in FIG. A hollow fiber membrane array 4 is formed. Further, in the present embodiment, such a hollow fiber membrane array 4 has a lateral direction (vertical direction in FIGS. 2 and 3 perpendicular to the lateral direction to which the hollow fiber membrane 2 is passed. A direction toward the back (hereinafter referred to as a parallel direction) is arranged in parallel in a plurality of rows and adjacent rows with an interval between the end portions 2A of the hollow fiber membranes 2.

  However, the hollow fiber membranes 2 passed in the lateral direction are not tensioned between the pair of fixing portions 3, and therefore the parallel direction is also applied between the plurality of hollow fiber membrane rows 4. The hollow fiber membranes 2 adjacent to each other may overlap each other. In addition, in the end portions 2A of the hollow fiber membranes 2 fixed to the fixing portion 3, the interval between the end portions 2A adjacent in the longitudinal direction in one hollow fiber membrane row 4 is the same as the hollow fiber membrane adjacent in the parallel direction. It is made smaller than the space | interval between the edge parts 2A of 4 rows.

  And under the hollow fiber membrane 2 fixed to the fixing | fixed part 3 in this way, the diffuser tube 5 is arrange | positioned as an aeration means in this embodiment. In the present embodiment, the air diffuser 5 is arranged at the lower part of each of the pair of fixing parts 3 so as to extend in the parallel direction at least at the part where the hollow fiber membrane 2 is fixed. For example, air is discharged from a plurality of nozzle holes provided at the lower edge of the connected air, and the air thus diffused becomes a bubble flow as shown by arrows in FIGS. 1 and 4. Ascending along the inner side surface 3A of the fixed portion 3. In this embodiment, at least during filtration, air is always sent from the air supply pipe to the air diffusion pipe 5 so that air is continuously diffused.

  On the other hand, below the hollow fiber membrane 2 passed between the pair of fixed portions 3, on the inner side of the two end portions 2A, that is, on the inner side of the air diffusing tube 5, as other air diffusing means in the present embodiment. An air diffuser 6 is provided. The air diffuser 6 extends horizontally in the lateral direction to which the hollow fiber membrane 2 is passed, and is disposed below the air diffuser 5 with a space between the air diffuser 2 and the hollow fiber membrane 2. In the same manner as the air diffuser 5, it is connected to an air supply pipe (not shown) to spout air, and the air diffused in this way is also converted into a bubble flow of the hollow fiber membrane 2 as indicated by white arrows in FIG. The part inside the end 2A is raised.

  In addition, the air diffused by the air diffuser 6 as another air diffuser is automatically performed according to the contamination of the hollow fiber membrane 2 as the filtration proceeds or at regular intervals. Thus, the air diffused by the air diffuser 5 is continuously performed during the air diffused by the air diffuser 6 as shown in FIG. However, the amount of air diffused by the air diffuser 5, that is, the amount of air discharged (the amount of air supplied from the air supply tube) is very small, and for example, simultaneously with the air diffuser 6 as another air diffuser. If air is diffused, the amount of air diffused from the air diffuser 6 is reduced.

  Such a filtration module 1 may be used alone for the filtration of raw water, but is used, for example, as one of the filtration modules of the filtration unit 11 of the embodiment shown in FIGS. 6 and 7. The filtration unit 11 of this embodiment is installed in a water tank or the like (not shown) in which the raw water W is held, and a bottomed cylindrical casing 12 into which the raw water W in the water tank or the like can be introduced, A plurality of filtration modules including the filtration module 1 housed in the casing 12.

  The casing 12 is made of a highly corrosive metal material such as stainless steel and has a rectangular shape in plan view, and the height of the casing 12 is increased with respect to the length of the rectangle. The bottom rectangular cylinder, that is, the bottom of the rectangular cylinder is closed, and the bottom is faced down and the height direction thereof is directed in the vertical vertical direction. Further, an inlet 13 for introducing the raw water W into the casing 12 is provided at the upper part of the casing 12, and the inlet 13 has a control means such as a butterfly valve for controlling the flow of the raw water W. The inlet 13 has a height that opens to the water surface H of the raw water W held in a water storage tank or the like, more specifically, a height that is submerged slightly below the water surface H. The casing 12 is installed.

  In such a casing 12, the plurality of filtration modules are arranged so that the lateral direction in which the hollow fiber membrane 2 is passed along the long side direction of the rectangle that the casing 12 is in a plan view, and the fixed portions of each other In this embodiment, four stages are stacked such that 3 are arranged in the vertical direction, that is, in the height direction, and only the lowermost filtration module is the filtration module 1 of the above embodiment. In addition, the other filtration module 14 other than this is set as the structure similar to the filtration module 1 of embodiment except the said diffuser tubes 5 and 7 being not provided. Therefore, the air diffuser 5 as the air diffuser of the filtration module 1 is disposed below the end portion 2A of the hollow fiber membrane 2 for all of the filtration modules 1 and 14. The air diffuser 6 as another air diffuser is disposed at the inner bottom of the casing 12 below the air diffuser 5.

  Further, the filtration unit 11 is supplied with activated carbon in the raw water W introduced into the casing 12 and added with a discharge means (not shown) for discharging the raw water W in the casing 12 after the physical cleaning by the diffuser 6. And an activated carbon supply means (not shown). Among these, the discharge means is, for example, a discharge pipe connected to a suction pump having one end opened at the bottom of the casing 12 and the other end disposed outside the casing 12, and the activated carbon supply means is, for example, a powder The turbid liquid in which the activated carbon is turbid is supplied to the raw water W in the casing 12.

  In the filtration unit 11 configured as described above, the filtration module 1 of the present embodiment is disposed at the lowest stage of the plurality of filtration modules 1, 14, and the end 2 </ b> A of the hollow fiber membrane 2 in the filtration module 1. The air diffused from the air diffuser 5 attached to the lower part of the fixed part 3 below, as shown in FIG. 1, concentrated on the end 2A of the hollow fiber membrane 2 in the filtration module 1 as described above. It is possible to suppress the deposition of turbidity by acting a bubble flow. Further, the bubble flow acting on the end 2A of the hollow fiber membrane 2 in the lowermost filtration module 1 ascends as it is as shown by the arrow in FIG. 6 and the upper filtration module 14 also has the hollow fiber membrane. Therefore, even if all the individual filtration modules 1 and 14 are not provided with a diffuser means (aeration tube 5), all of the filtration modules 1 and 14 housed in such a manner are used. Turbid deposits can be prevented.

  Therefore, according to the filtration module 1 and the filtration unit 11 having the above-described configuration, it is possible to prevent the end portion 2A of the hollow fiber membrane 2 from being blocked due to the deposition of turbidity, and accordingly, the hollow fiber membrane Since it is possible to prevent further blockage from occurring due to the increase in the permeation flux in the other part of 2, it is possible to prevent the filtration efficiency from decreasing for a long time and to promote efficient filtration of the raw water W. It becomes possible. In particular, in the present embodiment, the air diffuser 5 as the air diffuser is disposed below the fixed portion 3 to which the end 2A of the hollow fiber membrane 2 is fixed, and the generated bubble flow is immediately applied as it is. Since it can be made to act on end part 2A of hollow fiber membrane 2, it becomes possible to aim at prevention of deposition of turbidity more effectively.

  In the present embodiment, since the air diffuser 5 of the filtration module 1 continuously diffuses air, the raw water W around the end 2A of the hollow fiber membrane 2 is always in a fluid state during the filtration of the raw water W. In combination with the air scrubbing effect caused by the bubble flow acting on the end portion 2A, it is possible to more reliably prevent turbidity deposition. On the other hand, even if such turbidity deposition is prevented, the hollow fiber membrane 2 is blocked during long-term filtration. In this case, the diffuser 6 as the other diffuser is used as shown in FIG. The hollow fiber membrane 2 is physically cleaned by generating a bubble flow as indicated by the white arrow in FIG. 6. Compared with the amount of air diffused by the air diffuser 6, the air diffuser 5 continuously diffuses. Since the amount of diffused air is small and very small, according to the present embodiment, the power of the blower or the like for supplying air to the diffuser tube 5 can be reduced, and therefore the running cost of the diffuser tube 5 that always diffuses air. Can be suppressed.

  Moreover, in the filtration module 1 of the present embodiment, a plurality of end portions 2A in which a plurality of hollow fiber membranes 2 are bundled are arranged in the vertical direction in the fixed portion 3 to form a hollow fiber membrane row 4. The hollow fiber membrane rows 4 are arranged in parallel so as to be spaced between the end portions 2A, and the hollow fiber membrane rows 4 thus spaced apart as shown by arrows in FIG. Since the bubble flow can be raised through the gap, even if the amount of air diffused from the air diffuser 5 is very small as described above, only the lowermost filtration module 1 among the plural stages of filtration modules 1 and 14 can be used. Even if only the aeration tube 5 is provided, it is possible to reliably suppress turbidity deposition at the end 2A of the hollow fiber membrane 2 in all the filtration modules 1 and 14.

  Moreover, in this embodiment, the activated carbon supply means which adds activated carbon to the raw | natural water W filtered by the filtration modules 1 and 14 is provided, and adsorption | suction of the organic substance etc. in the raw | natural water W is aimed at by the activated carbon added in this way. The filtration efficiency can be improved. Further, the activated carbon added in this manner also causes clogging by adhering to the end 2A of the hollow fiber membrane 2 in the filtration modules 1 and 14, but the filtration module 1 having the above-described configuration and the filtration unit including the filtration module 1 are used. 11, such adhesion of activated carbon can also be suppressed by the aeration means (aeration tube 5) provided under the end 2 </ b> A, and more efficient filtration of the raw water W as described above can be performed for a longer period of time. In this way, it is possible to carry out continuously.

  On the other hand, in the filtration unit 11 of the above embodiment, a plurality of filtration modules 1 and 14 including the filtration module 1 of the present embodiment are accommodated in a casing 12 installed in a water storage tank or the like. Since the inlet 13 of the raw water W is disposed at the upper part of the bottomed cylinder, relatively clear raw water W in which turbidity has settled to some extent in a water storage tank or the like is introduced into the casing 12 and filtered. can do. For this reason, deposition of turbidity on the hollow fiber membrane 2 including the end 2A itself can be suppressed, so that it is possible to achieve filtration by continuous operation for a longer period.

It is a side view of the state which diffuses only with the diffuser tube 5 at the time of filtration which shows one Embodiment of the filtration module of this invention. It is a top view of embodiment shown in FIG. FIG. 3 is an enlarged plan sectional view of a portion A in FIG. 2. It is the perspective view which looked at the A section in FIG. 2 from the downward direction. It is a side view of the state which diffuses with the diffuser tubes 5 and 7 at the time of the physical cleaning of embodiment shown in FIG. It is a side view of the state which diffuses only with the diffuser tube 5 of the filtration module 1 at the time of filtration which shows one Embodiment of the filtration unit of this invention. It is a side view of the state which diffuses with the diffuser tubes 5 and 7 of the filtration module 1 at the time of the physical cleaning of embodiment shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,14 Filtration module 2 Hollow fiber membrane 2A End part of hollow fiber membrane 2 3 Fixing part 4 Hollow fiber membrane row | line | column 5 Air diffuser (air diffuser)
6 Air diffuser (other air diffuser)
11 Filtration unit 12 Casing

Claims (8)

  A plurality of hollow fiber membranes passed in the raw water in the lateral direction are bundled at their ends and fixed to the fixed portion, and an air diffuser is disposed below the ends of the bundled hollow fiber membranes. A filtration module characterized by being provided.   The filtration module according to claim 1, wherein the air diffuser continuously diffuses air.   The filtration module according to claim 1, wherein the air diffuser is disposed at a lower portion of the fixing portion.   A plurality of hollow fiber membrane bundle ends arranged in a vertical direction on the fixed portion to form a hollow fiber membrane row, and the hollow fiber membrane row is formed between the end portions. The filtration module according to any one of claims 1 to 3, wherein the filtration module is arranged in parallel in a plurality of rows at intervals.   Another air diffuser is disposed below the hollow fiber membrane between the ends, and the amount of air diffused by the air diffuser disposed below the ends is the other diffuser. The filtration module according to any one of claims 1 to 4, wherein the amount is less than the amount of air diffused by the means.   6. The filtration module according to claim 1, further comprising activated carbon supply means for supplying activated carbon to the raw water.   A plurality of filtration modules are stacked with the fixed portions of each other arranged in the vertical direction, and at least the lowermost filtration module is the filtration module according to any one of claims 1 to 6. A filtration unit characterized by.   The filtration unit according to claim 7, wherein the plurality of filtration modules are accommodated in a casing into which the raw water is introduced.

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