JP2014054605A - Membrane element, membrane module and membrane separation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane element, a membrane module and a membrane separation system capable of uniformly filtering water to be treated in a filtering membrane regardless of the specific resistance of the filter membrane.SOLUTION: There is provided a membrane element 10 which comprises: support means (housing 14) which supports a filtering membrane 12 which filters water to be treated to generate filtered water and has a space for storing the filtered water; a plurality of branch pipes 28 which are disposed and extended from the support means and allow the filtered water to flow; and a header pipe 30 having a water collecting port 32 which is connected in a state where the plurality of branch pipes 28 are disposed and allow the filtered water flowed in from the branch pipes 28 to flow out to the outside. The physical shape inside the header pipe 30 is changed so that the pressure losses from each of the branch pipes 28 to the water collecting port 32 are equal to one another.

Description

  The present invention relates to a membrane element, a membrane module, and a membrane separation system used for solid-liquid separation, and more particularly to a membrane element, a membrane module, and a membrane separation system used in membrane separation activated sludge treatment such as organic wastewater.

  Conventionally, in a membrane separation activated sludge treatment such as organic wastewater, an activated sludge membrane separation system (Membrane Bio Reactor System) in which a membrane module is arranged has been used. In this system, a membrane module for performing solid-liquid separation is arranged inside a reaction tank, and an air diffuser is provided below the membrane module. Here, the membrane module refers to a unit in which a plurality of membrane elements are integrated by arranging a plurality of membrane elements in parallel at regular intervals and accommodated in a casing. The membrane element is, for example, a device in which an opening provided in a housing is covered with a filtration membrane, and a pump that sucks filtered water contained in the housing with a negative pressure inside the housing is attached to the housing. is there. By driving this pump, the water to be treated is filtered, the filtered water passes through the filtration membrane, and suspended substances in the water to be treated are captured by the filtration membrane. And the clean filtration water permeate | transmitted through the filtration membrane and attracted | sucked by the housing | casing in a membrane element is taken out outside the reaction tank. In addition, an upward flow parallel to the surface of the filtration membrane is generated by the air lift action of the air bubbles diffused from the air diffusing device, and the deposits (suspended substances) are detached from the filtration membrane.

  In the above system, it is important to reduce the frequency of clogging of the filtration membrane and reduce the burden on the air diffuser by filtering the treated water uniformly over the entire filtration membrane to generate filtered treatment water. is there. However, on the surface of the filtration membrane, the pressure loss between the filtration membrane and the pump becomes non-uniform, and the water to be treated is filtered intensively at the portion of the filtration membrane where the pressure loss is close to the pump and suspended in that portion. Substances may adhere intensively.

  In order to solve this problem, in Patent Document 1, a plurality of branch pipes are extended from a housing having a filtration membrane as a part of the outer wall, and the branch pipes are connected to the header pipes and arranged in the header pipes. The membrane element which discharges the filtration treated water which the filtration membrane filtered from the water collection port is disclosed. The branch pipe is formed so that the cross-sectional area is smaller as the connection position with the header pipe is closer to the water collection port, or the branch pipe is installed so that the interval between the branch pipes is closer to the water collection port. ing. By setting it as the said structure, it is supposed that the variation of the pressure loss between branch piping is suppressed, and to-be-processed water can be filtered uniformly by the whole filtration membrane.

JP 2012-76005 A

  By the way, the pressure loss generated from the filtration membrane to the pump in the membrane element contributes almost equally to the filtration membrane, branch piping, and header piping. On the other hand, recently, a filtration membrane having a specific resistance reduced from that of the conventional one has been developed. Therefore, when such a filtration membrane is applied to the membrane element, the filtration membrane hardly contributes to the pressure loss of the entire membrane element. As a result, the pressure loss in the filtration membrane becomes non-uniform, the filtration proceeds intensively in a part of the filtration membrane, and the frequency of clogging of the filtration membrane and the burden on the air diffuser increase. .

  Accordingly, the present invention focuses on the above-described problems, and an object thereof is to provide a membrane element, a membrane module, and a membrane separation system that can uniformly filter water to be treated in the filtration membrane regardless of the specific resistance of the filtration membrane. To do.

  In order to achieve the above object, a membrane element according to the present invention supports a filtration membrane that filters treated water to generate filtered treated water, and has a support means having a space for accommodating the filtered treated water, A branch pipe that is arranged in a plurality from the support means and that flows out the filtered water, and a collection pipe that is connected in a state where a plurality of the branch pipes are arranged and that flows out the filtered water that flows in from the branch pipe to the outside. In a membrane element comprising a header pipe having a water port, the physical shape in the header pipe is changed so that the pressure loss from each branch pipe to the water collection port becomes equal to each other.

  With the above configuration, the pressure loss of the membrane element other than the filtration membrane can be made uniform, so that the water to be treated can be uniformly filtered regardless of the specific resistance of the filtration membrane. Can be prevented. Therefore, the cleaning operation of the filtration membrane surface by air diffusion is made efficient, and the entire filtration operation can be stabilized.

In the present invention, the header pipe includes a plurality of first flow rate adjusting means for circulating the filtered water, a first branch connected to the branch pipe, and a second outlet having the water collection port. A first partition plate that is partitioned into a compartment is disposed, and the first flow rate adjusting means has a smaller opening area as it is closer to the water collection port.
When there is no 1st partition plate, the pressure loss resulting from the distribution path from each branch piping to a water collection port is so small that it is close to a water collection port. Therefore, by setting it as the said structure, the pressure loss between branch piping can be equalize | homogenized with a simple structure, and to-be-processed water can be filtered uniformly in a filtration membrane.

In the present invention, a plurality of first flow rate adjusting means for circulating the filtered water is provided in the header pipe, and a first compartment connected to the branch pipe and a second compartment having the water collection port, The first partition plate is arranged, and the first flow rate adjusting means is characterized in that the installation interval becomes wider as it approaches the water collecting port.
When there is no 1st partition plate, the pressure loss resulting from the distribution path from each branch piping to a water collection port is so small that it is close to a water collection port. Therefore, by setting it as the said structure, the pressure loss between branch piping can be equalize | homogenized with a simple structure, and to-be-processed water can be filtered uniformly in a filtration membrane.

In the present invention, in the header pipe, the second compartment is divided into a third compartment having the first flow rate adjusting means and a fourth compartment having the water collection port and the filtration treatment. A second partition plate having a second flow rate adjusting unit through which water flows is disposed, and the second flow rate adjusting unit is located away from a straight line connecting the water collecting port and the first flow rate adjusting unit. It is characterized by being arranged in.
By the said structure, since the path | route from the branch piping in a header piping to a water collection port is further extended, the ratio with respect to the pressure loss of the difference of the pressure loss between branch piping can be reduced. Thereby, to-be-processed water can be filtered more uniformly in a filtration membrane.

In the present invention, the branch pipe has a smaller opening area as the connection position with the header pipe is closer to the water collection port.
With the above configuration, the pressure loss between the branch pipes can be made uniform with a simple configuration, and the water to be treated can be filtered uniformly in the filtration membrane.

In this invention, the connection space | interval between the said branch piping with respect to the said header piping becomes so wide that it approaches the said water collection port.
With the above configuration, the pressure loss between the branch pipes can be made uniform with a simple configuration, and the water to be treated can be filtered uniformly in the filtration membrane.

In the present invention, the support means is a casing having an opening sealed by the filtration membrane, and the casing includes a plurality of segments connected to at least one branch pipe among the branch pipes. It is characterized by being partitioned.
With the above configuration, in the flow path of the filtered treated water inside the support means, the component in the direction along the arrangement direction of the branch pipes can be reduced, and the component in the direction toward the branch pipe connected to the segment can be increased. . Thereby, the flow volume of the filtration process water which flows into each branch piping can be made more equal, and it can prevent that a difference arises in the degree of clogging in the surface of a filtration membrane.

On the other hand, the membrane module of the present invention is characterized in that a plurality of the membrane elements described above are arranged and housed in a casing.
With the above configuration, the membrane module can be immersed in the water to be treated, and membrane filtration can be performed with a plurality of membrane elements, the membrane surface cleaning operation by aeration can be made efficient, and a stable filtration operation can be performed.

In addition, the membrane separation system of the present invention is characterized by including the above-described membrane element.
With the above-described configuration, it is possible to improve the efficiency of the cleaning operation of the membrane surface by aeration, and it is possible to provide a membrane separation system in which the entire filtration operation is stabilized.

  According to the membrane element, the membrane module, and the membrane separation system according to the present invention, by changing the physical shape in the header pipe, the pressure loss when permeating the filtration membrane is made uniform, and the specific resistance of the filtration membrane Regardless of this, the water to be treated can be uniformly filtered in the filtration membrane.

It is a disassembled perspective view of the membrane element of 1st Embodiment. It is a block diagram of the membrane separation system of this embodiment. It is a schematic diagram of the membrane module in the reaction tank and reaction tank of this embodiment. It is a schematic diagram of the spacer in the housing | casing of this embodiment. It is a front view of the membrane element of a 1st embodiment. It is a front view of the membrane element of 2nd Embodiment. It is a front view of the membrane element of 3rd Embodiment. It is a front view of the membrane element of 4th Embodiment. It is a figure which shows the pressure loss of the membrane element of this embodiment, and distribution (case 1) of the filtration amount of the to-be-processed water in a filtration membrane. It is a figure which shows the pressure loss of the membrane element of this embodiment, and the distribution (case 2) of the filtration amount of the to-be-processed water in a filtration membrane. It is a figure which shows the pressure loss of the membrane element of this embodiment, and the distribution (case 3) of the filtration amount of the to-be-processed water in a filtration membrane.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. . In the drawings and the following description, it is assumed that the X axis (horizontal direction), the Y axis (horizontal direction), and the Z axis (vertical direction) are orthogonal to each other.

  FIG. 2 shows a block diagram of the membrane separation system of the present embodiment. The membrane separation system 100 of this embodiment includes an anaerobic tank 104 that is supplied with raw water by a raw water pump 102 and that temporarily releases phosphorus from activated sludge, an oxygen-free tank 106 that performs denitrification of raw water, and raw water. And a reaction tank 108 for decomposing organic substances in (treated water), removing phosphorus, and nitrifying ammonia. Here, the raw water is sent out in the order of the anaerobic tank 104, the anoxic tank 106, and the reaction tank 108. The anaerobic tank 104 is supplied with activated sludge (containing phosphorus) in the reaction tank 108, and the oxygen-free tank 106 is supplied with nitrified liquid (containing nitric acid) from the reaction tank 108 together with the activated sludge.

  In FIG. 3, the schematic diagram of the membrane module in the reaction tank and reaction tank of this embodiment is shown. As shown in FIG. 3, a partition plate 110 that divides the inside of the reaction tank 108 into two regions is disposed at the center of the reaction tank 108. A membrane tank region 113 in which the membrane module 112 is disposed is provided on one side across the partition plate 110, and an aerobic tank region 114 is provided on the other side.

  The membrane module 112 includes a plurality of membrane elements 10 that are erected in the Z-axis (vertical) direction and are arranged in parallel at regular intervals in the X-axis (horizontal) direction, and a casing that houses the plurality of membrane elements 10 116. In the membrane tank region 113, an air diffuser 118 that diffuses bubbles is provided at a position below the membrane module 112. When air bubbles are diffused into the membrane module 112 from the air diffuser 118, an accompanying action of water to be treated occurs when the air bubbles rise in the liquid. Further, a density difference between the gas-liquid two-phase flow generated in the membrane module 112 and the water to be treated outside the membrane module 112 in the membrane tank region 113 occurs. As a result, in the membrane tank region 113, a circulation flow is formed that rises inside the membrane module 112 and descends outside the membrane module 112. By this circulation flow, the membrane surface of the filtration membrane 12 (FIG. 1) is exposed to an upward flow parallel to the membrane surface, and the adhering matter on the membrane surface of the filtration membrane 12 is released by this upward flow.

  Above the membrane module 112, a pipe 120 connected to the water collection port 32 (FIG. 1) of each membrane element 10 and a treated water suction pump 122 attached to the pipe 120 are provided. The treated water suction pump 122 sucks the filtered treated water with a negative pressure inside the membrane element 10 and discharges the filtered treated water to the outside.

  In the aerobic tank region 114 in the reaction tank 108, a fine air diffuser 124 for dissolving oxygen in the water to be treated (raw water) is disposed. The fine air diffuser 124 emits fine air bubbles to maintain the dissolved oxygen concentration in the aerobic tank region 114 in the reaction tank 108 at a high concentration. In addition, activated sludge is mixed in the water to be treated in the reaction tank 108. The activated sludge in the reaction tank 108 performs an aerobic treatment that converts ammonia in the water to be treated into nitrate nitrogen while breathing dissolved oxygen in the water to be treated.

  FIG. 1 shows an exploded perspective view of the membrane element of the first embodiment. As shown in FIG. 1, the membrane element 10 of the present embodiment includes a casing 14 serving as a support means for supporting the filtration membrane 12, a plurality of branch pipes 28 extending from the casing 14, and branch pipes 28 in parallel. The entire header pipe 30 is connected. In FIG. 1, the + X-axis side wall of the header pipe 30 and the partition plate 48 (second partition plate) disposed in the header pipe 30 are omitted.

  The filtration membrane 12 receives the negative pressure from the main surface side on the −X axis side to filter the water to be treated from the main surface on the + X axis side to generate filtered water on the main surface side on the −X axis side. It is. The housing 14 supports the filtration membrane 12 and accommodates filtered water filtered from the filtration membrane 12. The casing 14 has a box shape and is erected in the Z-axis direction (vertical direction) in the reaction vessel 108. An opening 16 is formed on the side wall on the + X axis side of the housing 14, and the opening 16 is sealed with the filtration membrane 12.

  Further, inside the casing 14, a plurality of partition plates 18 are arranged side by side in the Z-axis direction with the main surface thereof facing the Z-axis direction. The partition plate 18 divides the housing 14 into six segments 20 in the Z-axis direction. By this segment 20, the component flowing in the Z-axis direction of the filtered water in the housing 14 can be reduced, and the component in the direction toward the branch pipe 28 connected to the segment 20 can be increased. Thereby, the flow volume of the filtration process water which flows into each branch piping 28 can be made more equal, and it can prevent that a difference arises in the clogging degree in the surface of the filtration membrane 12. FIG.

  In each segment 20, a plate-like spacer 22 (see FIGS. 4 and 5) is disposed, and the filtration membrane 12 is supported by the end face of the spacer 22 (the surface on the + X-axis side). Is prevented from bending. In FIG. 1, the opening 16 on the + X-axis side of the housing 14 is sealed with the filtration membrane 12, but the opening (not shown) is also formed on the side wall on the −X-axis side that is the back surface thereof. The opening (not shown) may be sealed with another filtration membrane (not shown), and the filtration membrane (not shown) may be supported by the end surface of the spacer 22 on the −X axis side.

  In FIG. 4, the schematic diagram of the spacer in the housing | casing of this embodiment is shown. As shown in FIG. 4, the spacer 22 is configured by connecting an elongated rectangular flat plate 24 vertically and horizontally. The short side of the flat plate 24 is connected to the housing 14 or the partition plate 18, and the long side supports (or bonds) the filtration membrane 12. The main surface of the flat plate 24 is oriented in the Y-axis direction or the Z-axis direction. The flat plate 24 is provided with a circular flow hole 26 penetrating in the thickness direction. Through this flow hole 26, the filtered water can flow through the segment 20. The shape of the flow hole 26 is not limited to a circle as shown in FIG. 4, and may be an ellipse, a rectangle, a polygon, or the like. In addition, the spacer 22 is not limited to the flat plate 24 provided with the flow holes 26, for example, a structure in which a large number of columns (rectangular columns) are arranged on the inner wall of the housing 14 and the filtration membrane 12 is supported by the end surface of the column, It may be a transparent structure.

  As shown in FIG. 1, the branch pipe 28 circulates the filtered water accommodated in the segment 20 to the header pipe 30 described later. The branch pipes 28 extend horizontally from the casing 14 in a form in which a plurality of branch pipes 28 are arranged side by side in the Z-axis direction on the side wall on the + Y-axis side of the casing 14. Further, at least one branch pipe 28 needs to be extended from each segment 20. In this embodiment, twelve branch pipes 28 are arranged, and each segment 20 is connected to two branch pipes 28. In addition, in FIG. 1, although the cross-sectional shape of branch piping is a rectangle, circular and other shapes are applicable.

  The header pipe 30 is a box-shaped casing that is erected in the Z-axis direction, similarly to the casing 14, and a branch pipe 28 is connected to the side wall in the −Y-axis direction. Thereby, the filtered water accommodated in the segment 20 flows into the header pipe 30 via the branch pipe 28. Further, a water collecting port 32 for discharging filtered water is provided at the upper end of the header pipe 30, and the above-described piping 120 is connected to the water collecting port 32.

  Therefore, by driving the treated water suction pump 122, the header pipe 30, the branch pipe 28, and the segment 20 can be set to a negative pressure, whereby the filtration membrane 12 filters the water to be treated and performs the filtration treatment. Water is generated in the segment 20, and the generated filtered water is discharged out of the membrane element 10 via the branch pipe 28 and the header pipe 30.

  In the membrane element 10, when the treated water suction pump 122 is driven, pressure loss occurs. The location where the pressure loss occurs is mainly the filtration membrane 12 and the flow path (branch pipe 28, header pipe 30) from the filtration membrane 12 to the water collection port 32. The pressure loss in the distribution channel increases as the length of the distribution channel increases, and increases as the cross-sectional area of the distribution channel decreases. For this reason, the pressure loss increases as the portion of the filtration membrane 12 is further away from the water collection port 32.

  Therefore, when the filtration operation is performed in this state, the filtration amount per unit time in the filtration membrane 12 becomes a different value for each position of the filtration membrane 12, the filtration amount becomes large at a specific place, and filtration is performed at other places. The amount can be reduced. In particular, as will be described later, when the pressure loss (specific resistance) of the filtration membrane 12 is sufficiently smaller than the pressure loss of the above-described flow path, filtration proceeds only at a specific location of the filtration membrane 12, There may be a case where filtration is not performed in the place. Therefore, in the present embodiment, in the header pipe 30, the physical shape in the header pipe 30 is changed so that the pressure loss from each branch pipe 28 to the water collection port 32 is uniform.

  FIG. 5 shows a front view of the membrane element of the first embodiment. 5 to 8, the filtration membrane 12 and the side wall on the + X axis side of the header pipe 30 are omitted. As shown in FIG. 5 (FIG. 1), the water collecting port 32 is disposed at a position on the + Y axis side of the outer wall of the header pipe 30 on the + Z axis side. In the header pipe 30, a partition plate 38 (first partition plate) is disposed that partitions the first compartment 34 connected to the branch pipe 28 and the second compartment 36 having the water collection port 32. .

  The partition plate 38 is a member having a longitudinal direction in the Z-axis direction, and slits 40 (or orifices) serving as a plurality of first flow rate adjusting means are formed along the longitudinal direction. In the present embodiment, eleven slits 40 are formed. The slit 40 has a smaller opening area as it is closer to the water collection port 32, that is, as it is disposed on the + Z-axis side. The pressure loss increases as the slit 40 has a smaller opening area.

  With the partition plate 38 of the present embodiment, the flow path of the filtered treated water flowing from one branch pipe 28 in the header pipe 30 can be divided into flow components that flow through the slits 40 individually. The flow path of the filtered treated water flowing from the other branch pipe 28 can be divided into similar flow components. Accordingly, it can be considered that a flow amount of filtered treated water obtained by adding the flow components from the branch pipes 28 flows to each slit 40. Each flow component follows a path from the branch pipe 28 to the water collecting port 32 via the corresponding slit 40.

  For example, considering the flow path of the filtered treated water flowing from the branch pipe 28 disposed at the top (most disposed on the + Z axis side), 11 flow components that individually flow through the slit 40 can be considered. Considering the flow component that flows through the slit 40 on the + Z-axis side, since the distance to the water collecting port 32 is the shortest, the component due to the length of the flow path in the pressure loss is small. However, since the opening area of the slit 40 is the smallest, the component resulting from the flow cross-sectional area of the flow path in the pressure loss (opening area of the slit 40 that causes rate control) is large.

  Conversely, considering the flow component flowing through the slit 40 on the most −Z axis side, the opening area of the slit 40 is the largest, so the component due to the flow cross-sectional area of the flow path in the pressure loss is small. However, since the distance to the water collecting port 32 is the longest, the component resulting from the length of the distribution path in the pressure loss is large. Therefore, the partition plate 38 distributes the filtered treated water flowing in from the branch pipe 28 arranged first from the top through all the slits 40, but generates a certain pressure loss in each distribution path. Therefore, a large pressure loss is generated with respect to the suction of the filtered water flowing in from the branch pipe 28 arranged first from the top.

  Next, considering the flow path of the filtered treated water flowing in from the branch pipes 28 arranged from the second onward, the slit which is on the + Z-axis side from the straight line connecting the outlet of each branch pipe 28 and the water collection port 32. The path that circulates 40 is longer than the above-mentioned straight line and the opening area of the slit 40 is small, so there is almost no flow component that circulates through the slit 40, and the slit 40 that is on the −Z-axis side from the above-mentioned straight line. Most of the distribution components are distributed.

  For example, as shown in FIG. 5, when considering the outlet of the seventh branch pipe 28 and the straight line 42 from the top, from the top slit 40 to the fourth slit 40 arranged on the + Z axis side from the straight line 42. The filtered water that flows in from the branch pipe 28 hardly circulates. Therefore, the partition plate 38 acts so that the filtered water that flows from the branch pipe 28 arranged on the −Z-axis side in the filtered water that flows from the branch pipe 28 has a smaller pressure loss for the suction.

  Moreover, when there is no partition plate 38, the pressure loss with respect to the suction | inhalation becomes so large that the filtered water which flowed in from the branch piping 28 arrange | positioned at the -Z-axis side. Therefore, by disposing the partition plate 38 of the present embodiment in the header pipe 30, it is possible to equalize the pressure loss with respect to the suction of the filtered water flowing from each branch pipe 28. Therefore, the amount of filtration in each segment 20 can be made uniform, and the uniformity of filtration of the treated water in the filtration membrane 12 can be improved.

  FIG. 6 shows a front view of the membrane element of the second embodiment. As shown in FIG. 6, the arrangement form of the slits 40 in the partition plate 38 may be different from the arrangement form shown in FIGS. 1 and 5. That is, although the opening area of the slit 40 formed in the partition plate 38 is common, it arrange | positions so that an installation space | interval may become so wide that the water collection port 32 is approached. In other words, the arrangement interval is narrowed toward the -Z axis side.

  By setting it as such a structure, the flow-through component which detours largely becomes so large that the filtered water flowed in from the branch piping 28 arrange | positioned at the + Z-axis side, Therefore A pressure loss becomes large. Conversely, the filtered water that flows in from the branch pipe 28 arranged on the −Z-axis side has a smaller flow component that bypasses, and thus the pressure loss is reduced. Therefore, similarly to the above, the pressure loss with respect to the suction of the filtered water flowing from each branch pipe 28 can be made uniform.

  The first embodiment shown in FIGS. 1 and 5 and the second embodiment shown in FIG. 6 can be realized simultaneously. That is, the slit 40 arranged in the partition plate 38 can be made smaller as the opening area is closer to the water collection port 32, and the installation interval of the slits 40 can be made wider as it is closer to the water collection port 32. Thereby, the effect of equalizing the amount of water to be treated in each segment 20 can be further enhanced.

  As shown in FIGS. 5 and 6, the header pipe 30 has a second compartment 36, a third compartment 44 having a slit 40 (first flow rate adjusting means), and a water collection port 32. A partition plate 48 (second partition plate) provided with a slit 50 (second flow rate adjusting means) through which filtered water flows while being divided into a fourth compartment 46 is disposed. The slit 50 (or an orifice) is arranged at a position away from a straight line connecting the water collecting port 32 and the slit 40 (first flow rate adjusting means).

  By configuring in this way, the linear flow path from the slit 40 to the water collecting port 32 is blocked, and the route from the branch pipe 28 in the header pipe 30 to the water collecting port 32 is further extended. The ratio of the pressure loss difference between them to the pressure loss can be reduced. As a result, the water to be treated can be filtered more uniformly in the filtration membrane 12.

  The opening area and installation interval of the slit 40 and the slit 50 are the specific resistance of the filtration membrane 12 to be applied, the position of the branch pipe 28, the flow rate and viscosity resistance of the water to be treated, and the output of the treated water suction pump 122. It is designed as appropriate in consideration of the above.

  7 and 8 show front views of the membrane elements of the third and fourth embodiments. As shown in FIG. 7 and FIG. 8, similarly to the slit 40, the branch pipe 28 is made smaller as the opening area (cross-sectional area) is closer to the water collection port 32 (third embodiment), and the arrangement of the branch pipe 28 is performed. It can arrange | position so that a space | interval may become so wide that it approaches the water collection port 32 (4th Embodiment). Thus, by changing the physical shape of the branch pipe 28 as well as the header pipe 30, the pressure loss in the flow path from each branch pipe 28 (each segment 20) to the water collection port 32 can be made uniform efficiently. The filtration membrane 12 can highly uniformly filter the water to be treated. As described above, the third embodiment and the fourth embodiment can be realized simultaneously.

The inventor of the present application investigated the distribution of the amount of water to be treated in the filtration membrane 12 of the membrane element 10 by simulation. Configurations to be applied include case 1 to case 3, and each case has the above-described filtration membrane 12, casing 14, branch pipe 28, and header pipe 30, and the inside of the casing 14 includes six cases. It is divided into segments 20. The liquid to be filtered was water (viscosity: 0.001 kg / m · s). In the case 1, as in the fourth embodiment, the installation interval and the opening area of the branch pipe 28 are changed, the partition plates 38 and 48 in the header pipe 30 are removed, and the specific resistance of the filtration membrane 12 is 1.5 × 10. ¹⁴ [1 / m] (same configuration as Patent Document 1). In Case 2, in the configuration of Case 1, the specific resistance of the filtration membrane 12 was set to 1.4 × 10 ¹² [1 / m]. In the case 3, the partition plate 38 (slit 40) is arranged in the header pipe 30 in the configuration of the case 2.

  9 to 11 show the pressure loss of the membrane element of this embodiment and the distribution of the amount of water to be treated in the filtration membrane. 9 to 11, the speed distribution of the filtered water in the filtration membrane 12 that represents the speed range of the filtered water that passes through the filtration membrane 12 in each segment 20 in 20 stages for each case, and the Z-axis direction. The graph of the pressure loss of the filtration membrane 12 in Fig. 8, and the pressure loss of the branch pipe 28 and the header pipe 30 in the Z-axis direction is shown. In the graph, since a continuous line is drawn, a step is generated at the boundary of the segment 20. Further, the pressure loss in the filtration membrane 12 is proportional to the square of the speed of the filtered water.

  As shown in FIG. 9, in case 1, since the branch pipes 28 have the configuration of the fourth embodiment, the pressure loss in the flow path from each branch pipe 28 toward the water collection port 32 is made uniform to some extent. . However, the pressure loss in the distribution path is the smallest (less than 500 Pa) in the distribution path connected to the uppermost segment 20 and increases as the lower segment 20 is moved (up to a little less than 1500 Pa). As a result, in the filtration membrane 12, the pressure loss is the largest in the portion belonging to the uppermost segment 20, and the pressure loss becomes smaller as it moves to the portion belonging to the lower segment 20.

However, in case 1, as can be seen from the graph, the pressure loss of the filtration membrane 12 changes in the range of slightly less than 3000 Pa to less than 4000 Pa, and as can be seen from the distribution diagram of FIG. It changes in the range of 1.4 × 10 ⁻⁵ m / s. Thereby, in case 1, it turns out that the to-be-processed water is filtered comparatively uniformly in the filter membrane 12.

  As can be seen from the graph of FIG. 9, in the case 1, the pressure loss in the filtration membrane 12 is about 2 to 3 times larger than the pressure loss in the branch pipe 28 and the header pipe 30. Therefore, by adjusting the pressure loss of the branch pipe 28, the contribution of the filtration membrane 12 to the pressure loss of the entire membrane element 10 can be adjusted for each segment 20, thereby making the pressure loss in the filtration membrane 12 uniform to some extent. It is possible to do.

  On the other hand, in the case 2, the specific resistance of the filtration membrane 12 is almost 1/100 that in the case 1. Thereby, most of the pressure loss of the membrane element 10 is occupied by the branch pipe 28 and the header pipe 30, and the filtration membrane 12 hardly contributes to the pressure loss. Thus, when the pressure loss of the filtration membrane 12 is significantly smaller than the pressure loss of the branch pipe 28 and the header pipe 30, the filtration membrane 12 against the pressure loss of the entire membrane element 10 is adjusted even if the pressure loss of the branch pipe 28 is adjusted. It is difficult to change the contribution of each segment 20. Therefore, the pressure loss in the filtration membrane 12 is remarkably small although it occurs at almost the inverse ratio of the pressure loss of the branch pipe 28 and the header pipe 30.

  In case 2, as shown in the graph of FIG. 10, in the filtration membrane 12, the pressure loss is generated in the portion belonging to the third segment 20 from the top where the pressure loss derived from the flow path is relatively small. In the portion belonging to the segment 20 below that, almost no pressure loss occurs.

  Therefore, as shown in the distribution diagram of FIG. 10, in the filtration membrane 12, the water to be treated is filtered at the portion belonging to the third segment 20 from the top where the pressure loss of the branch pipe 28 and the header pipe 30 is relatively small. It can be seen that almost no filtration is performed in the portion belonging to the fourth and subsequent segments 20 in which the pressure loss of the branch pipe 28 and the header pipe 30 is relatively large.

  If the filtration is continued in this state, the filtration proceeds at the portion belonging to the third segment 20 from the top of the filtration membrane 12, and the activated sludge in the water to be treated adheres to the membrane surface. Therefore, clogging progresses intensively in that portion, and the burden on the air diffuser 118 increases.

  Therefore, in the case 3, the partition plate 38 (slit 40) described above is arranged in the header pipe 30. In the case 3, the partition plate 38 (slit 40) in the header pipe 30 can give a large pressure loss to the suction of filtered water flowing from the branch pipe 28 close to the water collection port 32.

  As shown in the graph of FIG. 11, in the case 3, the pressure loss in each segment 20 (the branch pipe 28 and the header pipe 30) can be made substantially uniform. Thereby, the pressure loss in the filtration membrane 12 also remains in the range of 10 Pa to 40 Pa, and can be made more uniform than in the case 2. Therefore, as shown in the distribution diagram of FIG. 11, it is understood that the water to be treated is filtered in all the segments 20. In particular, it can be seen that the second to sixth segments 20 from the top are almost uniformly filtered. Moreover, compared with case 2, the pressure loss at the time of permeation | transmitting a filtration membrane is averaged, and it turns out that it is filtering uniformly.

  The partition plate 38 (slit 40) of the present embodiment can give pressure loss to the flow path from the branch pipe 28 to the water collection port 32, but also changes not only the cross-sectional area of the flow path but also the length of the flow path. Therefore, the amount of change in pressure loss can be made larger than in the case of adding a configuration for changing the pressure loss only to the branch pipe 28 as in Case 1 and Case 2. Therefore, in the case 3, even if the structure for changing the pressure loss is not added to the branch pipe 28, the pressure loss for the segment 20 (the branch pipe 28 and the header pipe 30) is made uniform only by the partition plate 38 (slit 40). Can be easily performed. Of course, the pressure loss can be made uniform more easily by adding the above-described configuration for changing the pressure loss not only to the partition plate 38 but also to the branch pipe 28 as in the case 3. Furthermore, by arranging the partition plate 48 (slit 50) in the header pipe 30, the pressure loss can be made more stable.

  In the present embodiment, the support means is the casing 14 that supports the filtration membrane 12, but this may be a support plate (not shown) in which a groove (not shown) is formed. The main surface of the support plate (not shown) is oriented in the X-axis direction. The main surface on the + X axis side of the support plate (not shown) has a plurality of grooves (not shown) that extend in the Y axis direction (horizontal) and that are arranged in parallel with each other and store filtered water. . Further, the aforementioned branch pipe 28 is attached to the side surface on the + Y-axis side of a support plate (not shown). And each groove | channel (not shown) is arrange | positioned so that the edge part may come to the connection position of the branch piping 28 of a support plate (not shown), and it can be set as the structure connected to the branch piping 28. FIG.

  Thus, when the treated water suction pump 122 is driven, the header pipe 30, the branch pipe 28, and the inside of the groove (not shown) become negative pressure, and the water to be treated is in a portion facing the groove (not shown) of the filtration membrane 12. The filtered water is filtered and stored in a groove (not shown), and the filtered water stored in the groove (not shown) is routed through the branch pipe 28 and the header pipe 30 from the water collection port 32 to the membrane element 10. It can be discharged to the outside.

  Membrane elements and membrane modules that make the pressure loss in the filtration membrane uniform by changing the physical shape in the header piping, and can uniformly treat the water to be treated in the filtration membrane regardless of the specific resistance of the filtration membrane And can be used as a membrane separation system.

10 ......... Membrane element, 12 ......... Filtration membrane, 14 ......... Case, 16 ......... Opening, 18 ......... Partition plate, 20 ......... Segment, 22 ......... Spacer, 24 ... ... Flat plate, 26 ... ... Flow hole, 28 ... ... Branch pipe, 30 ... ... Header pipe, 32 ... ... Water collecting port, 34 ... ... First compartment, 36 ... ... Second compartment, 38 ......... Partition plate, 40 ......... Slit, 42 ......... Line, 44 ......... Third compartment, 46 ......... Fourth compartment, 48 ......... Partition plate, 50 ......... Slit, 100 ……… Membrane separation system, 102 ……… Raw water pump, 104 ……… Anaerobic tank, 106 ……… Anoxic tank, 108 ……… Reaction tank, 110 ……… Partition plate, 112 ……… Membrane module, 113 ......... Membrane tank area, 114 ......... Aerobic tank area, 116 ......... Case, 118 ......... Air diffuser , 120 ......... pipe, 122 ......... treated water suction pump, 124 ......... fine diffuser.

Claims (9)

Supporting the filtration membrane for filtering the water to be treated to generate the filtered water, supporting means having a space for storing the filtered water, and a plurality of the extending means extending from the supporting means and the filtered water In a membrane element comprising: a branch pipe that flows out, and a header pipe that is connected in a state where a plurality of the branch pipes are arranged and has a water collecting port that flows out the filtered water that has flowed in from the branch pipe to the outside,
A membrane element, wherein the physical shape in the header pipe is changed so that the pressure loss from each branch pipe to the water collection port becomes equal to each other. In the header piping,
A first partition plate that includes a plurality of first flow rate adjusting means for circulating the filtered water, and is partitioned into a first compartment connected to the branch pipe and a second compartment having the water collection port. Arranged,
2. The membrane element according to claim 1, wherein the first flow rate adjusting unit has a smaller opening area closer to the water collection port. In the header piping,
A first partition plate that includes a plurality of first flow rate adjusting means for circulating the filtered water, and is partitioned into a first compartment connected to the branch pipe and a second compartment having the water collection port. Arranged,
The membrane element according to claim 1 or 2, wherein the first flow rate adjusting means has a larger installation interval as it approaches the water collection port. In the header piping,
Partitioning the second compartment into a third compartment having the first flow rate adjusting means and a fourth compartment having the water collecting port, and second flow rate adjusting means through which the filtered water flows. A second partition plate is provided,
The second flow rate adjusting means includes
The membrane element according to claim 2 or 3, wherein the membrane element is disposed at a position away from a straight line connecting the water collecting port and the first flow rate adjusting means.   The membrane element according to any one of claims 1 to 4, wherein an opening area of the branch pipe is smaller as a connection position with the header pipe is closer to the water collection port.   The membrane element according to any one of claims 1 to 5, wherein a connection interval between the branch pipes with respect to the header pipe becomes wider as it approaches the water collection port. The support means is
While being a housing having an opening sealed by the filtration membrane,
Inside the housing is
The membrane element according to any one of claims 1 to 5, wherein the membrane element is partitioned into a plurality of segments connected to at least one branch pipe among the branch pipes.   A membrane module comprising a plurality of membrane elements according to any one of claims 1 to 7 arranged in a casing.   A membrane separation system comprising the membrane element according to any one of claims 1 to 7.

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