WO2009118786A1 - Membrane module and membrane cassette - Google Patents

Abstract

A membrane module consists of multiple membrane units. Individual membrane units are detachably joined one to another by a joining member. Each of the membrane units has multiple membrane elements and holding members for fixing one side-edge portions of the membrane elements. Between membrane elements of each membrane unit, there are disposed those of the joint partner membrane unit.

Description

Membrane module and membrane cassette

The present invention relates to a submerged membrane module used for solid-liquid separation in, for example, sewage treatment or sludge concentration, and a membrane cassette comprising a plurality of membrane modules.

As a conventional membrane module, for example, as shown in FIGS. 20 and 21, one fixing member 11, the other fixing member 12, and a plurality of membranes provided in parallel between both the fixing members 11 and 12. Some have an element 13. The membrane elements 13 are arranged with a predetermined gap A therebetween.

In each of the fixing members 11 and 12, water collecting spaces 14 and 15 are formed, respectively. One side of each membrane element 13 is fixed to one fixing member 11 and reaches one water collecting space 14. Further, the other side portion of each membrane element 13 is fixed to the other fixing member 12 and reaches the other water collecting space 15. The inside of each membrane element 13 communicates with one water collecting space 14 in one fixing member 11 and the other water collecting space 15 in the other fixing member 12.

As shown in FIG. 22, the membrane module 10 as described above is installed in a treatment tank 19 and immersed in a liquid to be treated 24 (for example, an activated sludge mixed liquid). In addition, an air diffuser 20 that ejects air is provided below the membrane module 10. An upstream end of the extraction pipe 21 is connected to the fixing members 11 and 12, and a permeate storage tank 22 is installed at the downstream end of the extraction pipe 21. A suction pump 23 is provided in the middle of the extraction pipe 21.

According to this, when the suction pump 23 is driven and the inside of each membrane element 13 is decompressed by suction from the water collection spaces 14 and 15, filtration is performed, and solid matter such as sludge in the liquid to be treated ( The permeate from which the foreign matter) has been removed permeates through each membrane element 13, is collected in the water collection spaces 14, 15, and is stored in the permeate storage tank 22 from the water collection spaces 14, 15 through the extraction pipe 21. Is done.

Further, by ejecting air bubbles from the air diffuser 20, an upward flow is generated between the membrane elements 13 by the air lift action, and the membrane surface of each membrane element 13 is washed by this upward flow.

Note that Japanese Published Patent Publications (JP-A-11-33370, JP-A-6-319958) disclose a membrane module having the above-described configuration.

By the way, in the membrane module 10, solid matter (foreign matter) such as a sludge cake is accumulated between the membrane elements 13 due to poor sludge properties, excessive suction pressure, or filtration operation with insufficient amount of aeration. The efficiency is lowered, and the membrane elements 13 are clogged with solids such as a sludge cake, and filtration may not be possible. In such a situation, even if an upward flow is generated by the air diffuser 20 as described above, it is difficult to remove solid matter such as sludge cake accumulated between the membrane elements 13, and the operator The membrane module 10 was pulled up from the treatment tank 19, and solids such as sludge cake deposited between the membrane elements 13 were manually removed.

However, as shown in FIG. 21, when the gap A between the membrane elements 13 is narrow, there is a problem that it is difficult for an operator to remove solid matter such as sludge cake.

An object of the present invention is to provide a membrane module capable of easily removing solid matter (foreign matter) deposited between the membrane elements, and a membrane cassette comprising such a membrane module.

In order to achieve the above object, the membrane module in the first invention has a plurality of membrane units connected in a separable manner,
Each membrane unit has a plurality of membrane elements and a fixing member that fixes one end of the plurality of membrane elements,
Between the membrane elements of the membrane unit, the membrane elements of the membrane unit to be connected are arranged with their fixing members facing each other.

According to this, the membrane member of another membrane unit of the connection partner is arranged between the membrane elements of the membrane unit, with the fixing member of the membrane unit facing the fixing member of another membrane unit of the counterpart of connection, A membrane module is assembled by connecting the plurality of membrane units. At this time, a predetermined gap is formed between the membrane elements.

By immersing the membrane module in the liquid to be treated and depressurizing the inside of each membrane element, the liquid to be treated is filtered by each membrane element, and solid matter (foreign matter) such as sludge in the liquid to be treated is removed from each membrane. Captured by the element.

Further, by pulling up the membrane module from the treatment tank and separating the membrane module into a plurality of membrane units, a gap wider than the predetermined gap is formed between the membrane elements of each membrane unit. Thereby, between the membrane elements of each membrane unit can be easily washed, and the solid matter deposited between the membrane elements can be easily removed.

In particular, when the sludge between the membrane elements of the membrane module is clogged with sludge due to poor sludge properties or abnormal filtration operation, the membrane module is separated into a plurality of membrane units as described above. A gap that does not exist is generated, and cleaning becomes much easier.

The membrane module according to the second aspect of the present invention is one in which a plurality of identical membrane units are connected.

According to this, since the membrane module can be assembled by connecting the same membrane unit, the cost can be reduced.

In the membrane module according to the third invention, the membrane unit has a positioning portion for determining the position of the other end of the membrane element of the membrane unit to be connected.

According to this, when a plurality of membrane units are connected by the connecting member and the membrane module is assembled, the other end portion of the membrane element is positioned by the positioning portion, so that vibration of the membrane element can be prevented.

In the membrane module according to the fourth aspect of the present invention, a water collection space in which the permeate that has permeated through the membrane element is collected is formed inside the fixed member.

According to this, solid matter (foreign matter) such as sludge in the liquid to be treated is captured by the membrane element, and the permeate that has permeated the membrane element flows into the water collection space of the fixed member, and from the water collection space to the outside of the treatment tank To be taken out. For this reason, the pipe for water collection for collecting the permeated liquid from each membrane element can be simplified.

The fifth invention is a membrane cassette in which a plurality of membrane modules described in the fourth invention are arranged in a predetermined arrangement direction,
Fixing members of membrane modules adjacent to each other are detachably connected via a connecting portion,
The water collection spaces of the membrane modules adjacent to each other communicate with each other through a circulation hole formed in the connecting portion.

According to this, the permeate collected in the water collection space of each of the plurality of membrane modules flows to the water collection space of the specific membrane module through the flow hole of the connecting portion, and the water collection space of this specific membrane module To the outside of the treatment tank. For this reason, the pipe for water collection for collecting permeate from each membrane module can be simplified.

As described above, according to the present invention, when the membrane module is separated into a plurality of membrane units, the gap between the membrane elements is between the membrane elements when the membrane modules are assembled by connecting the plurality of membrane units. It becomes wider than the gap. For this reason, by separating the membrane module into a plurality of membrane units, the membrane elements of each membrane unit can be easily cleaned, and solid matter (foreign matter) deposited between the membrane elements can be easily removed. Can do.

The front view of the film | membrane cassette in the 1st Embodiment of this invention. The perspective view of a membrane cassette. The perspective view of the membrane module which comprises a membrane cassette. FIG. 2 is a partially cutaway front view of the membrane module. FIG. 5 is a VV arrow view in FIG. 4. The front view when dividing a membrane module into one division unit and the other division unit equally. FIG. 7 is a VV arrow view in FIG. 6. The longitudinal cross-sectional view of the membrane element of a membrane module. FIG. 6 is a V1-V1 arrow view in FIG. 5. FIG. 6 is a view taken along arrow V2-V2 in FIG. It is a longitudinal cross-sectional view of the connection part of a membrane module, and shows the state by which the fitting protrusion was inserted in the fitting hole. It is a longitudinal cross-sectional view of the connection part of a membrane module, and shows the state by which the fitting protrusion was removed from the fitting hole. The top view of the membrane module in the 2nd Embodiment of this invention. The top view when a membrane module is divided | segmented into one division unit and the other division unit equally. The front view when dividing a membrane module into one division unit and the other division unit equally. FIG. 2 is an enlarged plan view of the other positioning portion of the membrane module, where (a) shows a state when the membrane module is divided into two divided into one divided unit and the other divided unit, and (b) shows one divided unit. A state when the unit and the other divided unit are connected is shown. The top view of the membrane module in the 3rd Embodiment of this invention. The top view which isolate | separated the membrane module into three membrane units similarly. The top view of the membrane module in the 4th Embodiment of this invention. Perspective view of a conventional membrane module The VV arrow directional view in FIG. The figure which immersed the conventional membrane module in the processing tank.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, 31 is a membrane cassette, and this membrane cassette 31 is installed in a treatment tank 32 and immersed in a liquid to be treated 33 (for example, an activated sludge mixed solution). The membrane cassette 31 is composed of a plurality of membrane modules 34 stacked in the vertical direction C (an example of a predetermined arrangement direction).

As shown in FIG. 3 to FIG. 5, each membrane module 34 includes one fixing member 35a, the other fixing member 35b, and a plurality of membrane elements provided in parallel between both the fixing members 35a and 35b. 36a, 36b. 6 and 7, the membrane module 34 can be separated into two membrane units 38a and 38b, and these membrane units 38a and 38b are connected by a plurality of connecting members 55.

As shown in FIG. 6 and FIG. 7, one membrane unit 38a and the other membrane unit 38b are respectively composed of a plurality of membrane elements 36a, 36b and one side end portions (base end portions) of the membrane elements 36a, 36b. And fixing members 35a and 35b for fixing. The fixing members 35a and 35b are both rectangular box-shaped members having an upper wall 41, a lower wall 42, a front wall 43, a rear wall 44, an outer wall 45, and an inner wall 46, and a water collecting space 48a therein. , 48b.

As shown in FIG. 8, the membrane elements 36 a and 36 b have a rectangular flat filter plate 50 and a filter membrane 51 made of a flat membrane attached to both the front and back surfaces of the filter plate 50. On both the front and back surfaces of the filter plate 50 of the membrane element 36a of the one membrane unit 38a, a horizontal permeate flow passage 52 communicating with the one water collection space 48a is formed. Similarly, a horizontal permeate flow passage 52 communicating with the other water collecting space 48b is formed on both the front and back surfaces of the filter plate 50 of the membrane element 36b of the other membrane unit 38b.

As shown in FIG. 9, one end of one membrane element 36a passes through the inner wall 46 and reaches one water collecting space 48a. Thereby, one membrane element 36a is fixed to one fixing member 35a. The other end (tip) and the upper and lower ends of one membrane element 36a are sealed so that the liquid to be treated 33 does not directly enter the permeate flow passage 52.

Similarly, as shown in FIG. 10, one end portion of the other membrane element 36b passes through the inner wall 46 and reaches the other water collecting space 48b. Thus, the other membrane element 36b is fixed to the other fixing member 35b. The other end (tip) and the upper and lower ends of the other membrane element 36b are sealed so that the liquid 33 to be treated does not directly enter the permeate flow passage 52.

4 and 5, the membrane element of the other membrane unit 38b (an example of another membrane unit to be connected) is interposed between the membrane elements 36a of one membrane unit 38a (an example of any membrane unit). 36b is arranged so that the membrane element 36a of one membrane unit 38a and the membrane element 36b of the other membrane unit 38b are alternately arranged, so that one membrane unit 38a and the other membrane unit 38b are arranged. And are connected.

Each connection member 55 includes connection plates 56a and 56b provided at both front and rear ends of the fixing members 35a and 35b, connection rods 57 inserted through through holes 59a and 59b formed in the connection plates 56a and 56b, and a connection. It consists of nuts 58a and 58b screwed to both ends of the rod 57.

As shown in FIGS. 4 and 5, in the state where one membrane unit 38a and the other membrane unit 38b are connected, the membrane element 36a of one membrane unit 38a and the membrane element 36b of the other membrane unit 38b facing each other. Are arranged in parallel with a predetermined gap A therebetween. A channel 61 having a width of the predetermined gap A is formed between the membrane element 36a and the membrane element 36b.

Further, the inner wall 46 of one fixing member 35a is provided with a plurality of one positioning portions 62a for fixing the position of the other end (tip portion) of the other membrane element 36b to be connected. Similarly, the inner side wall 46 of the other fixing member 35b is provided with a plurality of other positioning portions 62b for fixing the position of the other end (tip portion) of one membrane element 36a to be connected. .

As shown in FIG. 7, each positioning portion 62a, 62b has a recess 63, and when one membrane unit 38a and the other membrane unit 38b are connected, the other side end of one membrane element 36a. Is fitted into the recess 63 of the other positioning portion 62b, and the other end of the other membrane element 36b is fitted into the recess 63 of the one positioning portion 62a.

Note that as the positioning portions 62a and 62b, comb-like spacing members made of rubber or resin may be fitted from at least one of the upper end portion and the lower end portion of the membrane elements 36a and 36b.

Further, as shown in FIGS. 3 to 5, one fixing member 35a is provided with one connecting portion 65a, and the other fixing member 35b is provided with the other connecting portion 65b. The plurality of membrane modules 34 are detachably connected via one and other connecting portions 65a and 65b and stacked in the vertical direction C.

As shown in FIGS. 11 and 12, the one and the other connecting portions 65a and 65b are provided on the upper surfaces of the fixing members 35a and 35b and protrude upward, and the cylindrical fitting protrusions 67 and the fixing members 35a, It comprises a fitting hole 68 provided on the lower surface of 35b.

The fitting protrusion 67 is detachable from the fitting hole 68 in the vertical direction C. The fitting hole 68 is formed in a cylindrical tubular member 72 provided on the lower wall 42. The upper end of the fitting hole portion 68 of one fixing member 35a opens to the water collecting space 48a, and the lower end opens to the lower surface of the fixing member 35a. Similarly, the upper end of the fitting hole portion 68 of the other fixing member 35b opens to the water collecting space 48b, and the lower end opens to the lower surface of the fixing member 35b.

One through-hole 75a that opens to the upper end of the fitting projection 67 and one water collection space 48a is formed in the fitting projection 67 and the upper wall 41 of one fixing member 35a. Similarly, the other protrusion hole 75b opened to the upper end of the fitting protrusion 67 and the other water collecting space 48b is formed in the fitting protrusion 67 and the upper wall 41 of the other fixing member 35b. . A seal member 76 (for example, an O-ring or the like) for sealing between the inner peripheral surface of the fitting hole 68 and the outer peripheral surface of the fitting protrusion 67 is provided on the outer periphery of each fitting protrusion 67. ing.

The seal member 76 may be provided not on the outer periphery of the fitting protrusion 67 but on the inner periphery of the fitting hole 68.

As shown in FIG. 11, one water collecting space 48a of the lower membrane module 34 and one water collecting space 48a of the upper membrane module 34 are one flow of the fitting projection 67 of one connecting portion 65a. It communicates through the hole 75a. Similarly, the other water collection space 48b of the lower membrane module 34 and the other water collection space 48b of the upper membrane module 34 are connected via the other flow hole 75b of the fitting projection 67 of the other connecting portion 65b. And communicate.

The one membrane unit 38a and the other membrane unit 38b have the same structure, shape, and dimensions.

2 and 3, water collecting pipes 78a and 78b are provided on the left and right outer sides of the uppermost membrane module 34, respectively. The fitting protrusions 67 of the fixing members 35a and 35b of the uppermost membrane module 34 and the water collecting pipes 78a and 78b are connected via connecting pipes 79a and 79b. The water collecting pipes 78a and 78b are connected to a permeated water outlet pipe (not shown), and the permeated water outlet pipe is connected to a suction pump (not shown).

In addition, gravity filtration which makes the driving force the water head pressure in the processing tank 32 can also be used for taking out permeated water.

As shown in FIGS. 1 and 2, an air diffuser 81 that ejects air is provided below the lowermost membrane module 34. The air diffuser 81 includes an air diffuser case 82 and an air diffuser 83 provided in the air diffuser case 82. In addition, the fitting hole 68 of the connection part 65a, 65b of the lowermost membrane module 34 is closed with a lid or the like.

Hereinafter, the operation of the above configuration will be described.

As shown in FIGS. 4 and 5, the connecting rod 57 is inserted through the through hole 59a of the connection plate 56a of one membrane unit 38a and the through hole 59b of the connection plate 56b of the other membrane unit 38b, and nuts 58a and 58b. Is screwed to both ends of the connecting rod 57, whereby the one membrane unit 38a and the other membrane unit 38b are connected to form the membrane module 34.

At this time, the membrane element 36b of the other membrane unit 38b is inserted between the membrane elements 36a of one membrane unit 38a, and the membrane elements 36a and the membrane elements 36b are alternately arranged with a predetermined gap A therebetween. .

Further, the other end of one membrane element 36a is fitted into the recess 63 of the other positioning portion 62b, and the other end of the other membrane element 36b is fitted into the recess 63 of the one positioning portion 62a. Thereby, the position of the other side edge part of each membrane element 36a, 36b is positioned and fixed, respectively, and vibration of each membrane element 36a, 36b can be prevented.

The method for forming the membrane module 34 is not limited to the above, and a method of constraining the other end of each membrane element 36a, 36b at the positioning portion, or each membrane unit 38a, Other methods are possible, such as a method of storing 38b.

As shown in FIGS. 3 and 12, when a plurality of membrane modules 34 are stacked up and down, the fitting hole 68 of the upper membrane module 34 is fitted into the fitting projection 67 of the lower membrane module 34 from above. .

Thus, as shown in FIG. 11, the lower membrane module 34 and the upper membrane module 34 are connected via the connecting portions 65a and 65b. As shown in FIG. The membrane cassettes 31 can be installed by stacking the membrane modules 34.

As shown in FIG. 2, the fitting protrusions 67 of the fixing members 35a and 35b of the uppermost membrane module 34 and the water collecting pipes 78a and 78b are connected via connecting pipes 79a and 79b. Thereafter, the suction pump is driven, the air diffuser 81 is operated, air is ejected from the air diffuser 83, and the filtration operation is started.

At this time, as shown in FIG. 11, one water collecting space 48a of the plurality of upper and lower membrane modules 34 connected to each other communicates with each other through one flow hole 75a, and the other water collecting space 48b is connected to the other. It communicates with each other through the circulation hole 75b.

For this reason, if a negative pressure is applied to the water collection spaces 48a and 48b of the uppermost membrane module 34 by the suction action of the suction pump, the negative pressure is applied to the water collection spaces 48a and 48b of all the connected upper and lower membrane modules 34. Act.

Thereby, the inside of each membrane element 36a, 36b is depressurized, and sludge and the like in the liquid 33 to be treated are captured by the filtration membrane 51 of each membrane element 36a, 36b. Among these, the permeated water that has passed through the filtration membrane 51 and has flowed into the permeate flow passage 52 of the membrane element 36a of the one membrane unit 38a serves as treated water from the permeate flow passage 52 to the water collecting space 48a of the one fixing member 35a. Flow into. Further, the permeated water that has passed through the filtration membrane 51 and has flowed into the permeated water flow passage 52 of the membrane element 36b of the other membrane unit 38b is treated water from the permeated water flow passage 52 to the water collecting space 48b of the other fixing member 35b. Flows in.

In this way, the permeated water (that is, treated water) collected in the water collection spaces 48a and 48b of the membrane modules 34 passes through the flow holes 75a and 75b of the fitting protrusions 67 of the connecting portions 65a and 65b. The water collecting spaces 48a and 48b of the lower membrane module 34 flow into the water collecting spaces 48a and 48b of the upper membrane module 34, and finally the water collecting space of the uppermost membrane module 34 (an example of a specific membrane module). The water flows into the water collecting pipes 78a and 78b through the connecting pipes 79a and 79b from 48a and 48b, flows from the water collecting pipes 78a and 78b to the permeated water extraction pipe, and is taken out of the processing tank 32.

Further, the membrane module 34 is lifted from the treatment tank 32, and as shown in FIGS. 6 and 7, nuts 58a and 58b are removed from the connecting rod 57, and one membrane unit 38a and the other membrane unit 38b are separated. The other membrane element 36b can be removed from between the one membrane element 36a. Thereby, a gap B (see FIG. 7) wider than the predetermined gap A (see FIG. 5) is formed between the one membrane element 36a of the one membrane unit 38a. For this reason, it is possible to easily clean one membrane element 36a. Similarly, a gap B wider than the predetermined gap A is formed between the other membrane elements 36b of the other membrane unit 38b. For this reason, it is possible to easily clean the space between the other membrane element 36b. Thereby, solid substances, such as sludge accumulated between each membrane element 36a, 36b, can be removed easily.

When the membrane module 34 clogged or damaged is replaced with a new membrane module 34, as shown in FIGS. 6 and 7, the membrane module 34 is replaced with one membrane unit 38a and the other membrane unit 38b. Dividing into two, each membrane unit 38a, 38b can be replaced with a new one for each membrane unit 38a, 38b with the minimum replacement unit. For this reason, compared with the case where it replaces | exchanges for a new thing for every membrane module 34 by making the membrane module 34 into the minimum replacement | exchange unit, cost can be saved.

4 and 5, the connecting rod 57 of each connecting member 55 is used as a handle in a state where the membrane module 34 is assembled by connecting one membrane unit 38a and the other membrane unit 38b. be able to. Thus, the operator can easily carry the membrane module 34 by grasping the connecting rod 57 by hand.

Furthermore, since one membrane unit 38a and the other membrane unit 38b have the same structure, shape, and dimensions, the cost can be reduced.

A second embodiment of the present invention will be described with reference to FIGS.

In the first embodiment, the water collecting spaces 48a and 48b are formed in both the fixing members 35a and 35b, respectively. However, the membrane module 34 of the second embodiment has one membrane unit. The water collecting space 48a is not formed inside the fixing member 35a of 38a, and the other water collecting space 48b is formed only inside the fixing member 35b of the other membrane unit 38b.

That is, the fixing member 35a of one membrane unit 38a is a flat plate-like member having a smaller thickness than the fixing member 35b of the other membrane unit 38b. The fixing member 35a is provided with a positioning portion 62a as in the first embodiment. The fitting protrusion 67 of one membrane unit 38a is a columnar member in which no flow hole is formed. In addition, although the fitting hole portion 68 is formed at the lower end portion of the fixing member 35a of the one membrane unit 38a, the cylindrical member 72 is not provided.

The positioning portion 62b of the other membrane unit 38b includes a positioning nozzle 89 provided at the other end of the membrane element 36a of the one membrane unit 38a, and the inner wall 46 of the fixing member 35b of the other membrane unit 38b. The positioning hole 90 is formed on the surface.

The positioning nozzles 89 are provided at a plurality of positions above and below the other end of the membrane element 36a. Each positioning nozzle 89 is formed with a communication hole 91 that communicates with the permeate flow passage 52 of the membrane element 36a.

The positioning hole 90 penetrates the inner wall 46 of the fixing member 35b of the other membrane unit 38b inward and outward, and is formed at a plurality of upper and lower portions. Each positioning nozzle 89 can be fitted into and removed from each positioning hole 90 in a watertight manner.

Hereinafter, the operation of the above configuration will be described.

As shown in FIG. 13, when the membrane module 34 is assembled by connecting one membrane unit 38a and the other membrane unit 38b, the other end of the membrane element 36b of the other membrane unit 38b is one membrane unit. The positioning nozzles 89 as the other positioning portions 62b are fitted into the positioning holes 90 in a watertight manner, as shown in FIG. 16 (b). Thereby, the position of the other side edge part of each membrane element 36a, 36b is positioned and fixed, and the vibration of each membrane element 36a, 36b can be prevented.

Further, after a plurality of membrane modules 34 are stacked vertically to form the membrane cassette 31, a negative pressure is applied to the other water collection space 48b of all the upper and lower membrane modules 34 by the suction action of the suction pump.

Thereby, the inside of each membrane element 36a, 36b is depressurized, and the sludge and the like in the liquid to be treated 33 are captured by the filtration membrane 51 of the membrane element 36a, 36b. The permeated water that has passed through the filtration membrane 51 and has flowed into the permeated water flow passage 52 of the membrane element 36a of one membrane unit 38a passes through the communication hole 91 of the positioning nozzle 89 from the permeated water flow passage 52 as the treated water. Flows into the water collection space 48b of the membrane unit 38b. Further, the permeated water that has permeated the filtration membrane 51 and has flowed into the permeate flow passage 52 of the membrane element 36b of the other membrane unit 38b flows from the permeate flow passage 52 into the other water collection space 48b as treated water.

In this way, in the membrane module 34 in which one water collecting space 48a is not formed inside the fixing member 35a of one membrane unit 38a, the permeated water of each membrane element 36a, 36b is collected by the other membrane unit 38b. It can be collected in the water space 48b. At this time, as shown in FIG. 16, in addition to the positioning function, the positioning portion 62b of the other membrane unit 38b collects the permeated water from the membrane element 36a of one membrane unit 38a. It also has a function of leading to the water space 48b.

In this way, the permeated water (that is, treated water) collected in the water collecting space 48b of the other membrane unit 38b of each membrane module 34 passes through the flow hole 75b of the fitting projection 67 of the connecting portion 65b. It flows from the water collecting space 48b of the lower membrane module 34 to the water collecting space 48b of the upper membrane module 34, and finally from the water collecting space 48b of the uppermost membrane module 34 (an example of a specific membrane module) to the connecting pipe 79b. Then, the water flows into the water collecting pipe 78b, flows from the water collecting pipe 78b to the permeated water outlet piping, and is taken out of the processing tank 32.

In each of the above embodiments, as shown in FIGS. 7 and 14, the membrane module 34 can be divided into two membrane units 38a and 38b. However, as a third embodiment, shown in FIGS. As described above, the membrane module 34 may be divided into three parts, that is, the first to third membrane units 38a to 38c. Moreover, the structure which can be divided into multiple more than three divisions may be sufficient.

In each of the above embodiments, as shown in FIGS. 5 and 13, one membrane element 36a and the other membrane element 36b are alternately arranged one by one, but all the membrane elements 36a and 36b are not necessarily one. The membrane elements 36a and 36b may be alternately arranged instead of being arranged alternately. For example, as a fourth embodiment, as shown in FIG. 19, two (a plurality of) one membrane element 36a and the other membrane element 36b may be alternately arranged.

In each of the above embodiments, the fixing members 35a and 35b are formed in a quadrangular shape, but may have a shape other than the quadrangular shape, for example, a semi-cylindrical shape, a triangular prism shape, a polygonal prism shape, or the like.

In each of the above embodiments, the plate-like membrane elements 36a and 36b are used, but a ceramic cylindrical membrane element may be used.

In each of the above-described embodiments, as shown in FIG. 2, the plurality of membrane modules 34 are connected via the connecting portions 65a and 65b and stacked in the vertical direction C. It is not limited to the up-down direction C, and the membrane modules 34 may be arranged in the front-rear direction or the left-right direction and connected via the connecting portions 65a, 65b. Alternatively, the membrane modules 34 may be used alone without being stacked.

In each of the above embodiments, the fixing members 35a and 35b of the uppermost membrane module 34 are connected to the water collecting pipes 78a and 78b via the connecting pipes 79a and 79b. The fixing members 35a and 35b of the lowermost membrane module 34 may be connected to the water collecting pipes 78a and 78b via the connecting pipes 79a and 79b.

Claims (5)

Multiple membrane units are separably connected,
Each membrane unit has a plurality of membrane elements and a fixing member that fixes one end of the plurality of membrane elements,
A membrane module, characterized in that a membrane element of a membrane unit to be connected is arranged with a fixing member facing each other between membrane elements of the membrane unit. The membrane module according to claim 1, wherein a plurality of the same membrane units are connected. The membrane module according to claim 1 or 2, wherein the membrane unit has a positioning portion for determining the position of the other end of the membrane element of the membrane unit to be connected. The membrane module according to any one of claims 1 to 3, wherein a water collection space in which the permeated liquid that has passed through the membrane element is collected is formed in the fixing member. A membrane cassette in which a plurality of membrane modules according to claim 4 are arranged in a predetermined arrangement direction,
Fixing members of membrane modules adjacent to each other are detachably connected via a connecting portion,
A membrane cassette characterized in that water collection spaces of membrane modules adjacent to each other communicate with each other through a circulation hole formed in a connecting portion.

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