Membrane module and membrane filtration device

Abstract

To provide a membrane module which even persons poor in specialized knowledge and experience can easily remove and clean a filtration membrane as necessary and which is less likely to be broken by repeated attachment and detachment of the filtration membrane; and a membrane filtration device which has inexpensive production cost and an excellent maintenance property.SOLUTION: A membrane module 100 provided with a filtration membrane includes: a membrane fixing part 2 which fixes an end part 11 of a filtration membrane 1; a housing 3 which houses the filtration membrane 1; and a cap 4 which detachably fixes the housing 3. The housing 3 is detachably attached to the cap 4 in a screw type or a bayonet type. The membrane fixing part 2 and the filtration membrane 1 are detachable concomitantly with detachment of the housing 3. Detachment of the filtration membrane 1 and the membrane fixing part 2 from the housing 3 can make the filtration membrane 1 as a whole in an exposed state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a membrane module equipped with a filtration membrane for obtaining colorless and transparent treated water by filtering water containing impurities such as suspended solids and salt, and a membrane filtration device using the same. [Background technology]

[0002] 2. Description of the Related Art In order to make polluted water such as river water or pond water suitable for drinking, membrane filtration devices have been developed that remove turbidity components using membrane modules incorporating filtration membranes such as hollow fiber membranes, and remove ions, viruses, etc. as necessary using membrane modules incorporating reverse osmosis membranes. Such membrane filtration devices are sometimes used to obtain drinkable fresh water from seawater or salt-containing groundwater, particularly in remote islands where drinking water is often in short supply.

[0003] Generally, in a membrane filtration device using a filtration membrane, as the filtration operation continues, impurities accumulate on the filtration membrane, reducing the filtration efficiency and possibly damaging the filtration membrane. Therefore, when impurities accumulate on the filtration membrane, the impurities accumulated on the filtration membrane are removed by performing backwashing, in which the treated water flows in the opposite direction, or bubbling, in which air bubbles are mixed into the water to be treated.

[0004] However, backwashing requires a backwash pump and a control device to control an electromagnetic valve to switch between filtration and backwashing, which increases manufacturing and installation costs.In addition, the impurities contained in the treated water can vary depending on the season and location, so the installer needs specialized knowledge and experience to properly set the duration of the backwashing operation and the time interval between the filtration operation.

[0005] Therefore, conventionally, a technique has been developed that allows anyone to easily clean the filtration membrane by removing the filtration membrane from the membrane module. For example, Patent Document 1 discloses a hollow fiber membrane module 900 comprising a flange 91 with a pipe, a housing 92, hollow fiber membranes 93, 93 . . . , outer cylinders 94, 94', and a seal cap 95, as shown in FIG.

[0006] In the hollow fiber membrane module 900 of Patent Document 1, since the pipe flange 91 has a plurality of holes 911·911..., it is considered that the pipe flange 91 and the housing 92 are fixed with bolts (not shown) and nuts (not shown). In other words, the housing 92 can be removed from the pipe flange 91 by removing the bolts. When the housing 92 is removed at this time, the seal cap 95 and the outer cylinder 94 are separated. Next, the outer cylinders 94·94' and the hollow fiber membranes 93·93... fixed thereto can be pulled out from the housing 92, whereby the hollow fiber membranes 93·93... can be removed and washed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 7-308549 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the membrane module of Patent Document 1, the seal cap is pressed against the outer cylinder by a fixing spring. That is, the outer cylinder and the hollow fiber membrane fixed thereto are subjected to a repulsive force from the seal cap during assembly. Therefore, when fixing the flange with the pipe and the housing with bolts and nuts, the bolts must be tightened with the housing pressed against the flange with the pipe. This work is thought to require at least two workers, resulting in poor work efficiency. The same is true when removing the housing; the bolts must be loosened while applying force to press the housing against the pipe flange.

[0009] Also, when the housing is attached to the flange with the pipe, the holes may become misaligned with respect to each other, and if the holes become misaligned, the housing must be rotated to align them. However, it is believed that the strong friction between the outer cylinder and the seal cap occurs when the outer cylinder is pressed by the fixed spring, and that the friction causes strong contact between them. Therefore, when the housing is rotated in a state where strong friction is generated, the seal cap rotates with the fixed spring, and the spring's restoring force twists the hollow fiber membrane, causing damage to the hollow fiber membrane.

[0010] As described above, a membrane filtration device equipped with a membrane module that is poor in operability and maintainability will experience breakdowns and problems in a short period of time when operated in, for example, remote islands of developing countries. In such areas, there are almost no people with knowledge or experience of filtration devices and filtration, and it is impossible for them to restart a membrane filtration device that has been stopped by themselves. As a result, the equipment manufacturer or a service agent must frequently respond to the customer's requests, which not only makes it difficult for the customer to make a living while they wait, but also increases their economic burden. This results in dissatisfaction for both the responding party and the party being served.

[0011] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a membrane module which allows even a person lacking in specialized knowledge or experience to easily remove and clean the filtration membrane as needed, and which is not easily damaged even when the filtration membrane is repeatedly attached and detached. Another object of the present invention is to provide a membrane filtration device which is inexpensive to manufacture and easy to maintain. [Means for solving the problem]

[0012] The means adopted by the present inventors to solve the above problems will be described below. The membrane module of the present invention is a membrane module equipped with a filtration membrane for obtaining treated water from impurity-containing water to be treated by removing the impurities. Its basic configuration includes a membrane fixing portion for fixing an end of the filtration membrane, a housing for accommodating the filtration membrane, and a cap for detachably fixing the housing. The housing is detachable from the cap by a screw or bayonet, and the membrane fixing part and the filtration membrane can be removed at the same time as the housing is removed. By removing the filtration membrane and the membrane fixing part from the housing, the entire filtration membrane can be exposed.

[0013] In the present invention, impurities refer to substances contained in the treated water that are unnecessary for the intended purpose of the water (for example, drinking or hand washing) and should be removed, and examples of such substances include suspended solids, ionic components, bacteria, and viruses. The bayonet type refers to a mechanism that can be attached and detached by fitting two corresponding members together and rotating them by a predetermined angle.

[0014] When a removable filtration membrane is attached, it must be installed watertight, otherwise the water outside the membrane and the water inside the membrane will mix and become impossible to filter. For this reason, a watertight structure may be realized by pressing a member such as a gasket or packing. However, when watertightness is achieved by pressing, the repulsive force against the filtration membrane acts in a direction that repels the cap through the housing when the housing is attached. In this state, if the housing and the cap are fixed with bolts and nuts, as described above, the bolts must be tightened while pressing the housing against the cap, which is inefficient.

[0015] In contrast, the membrane module of the present invention has a housing and a cap that can be attached and detached using a screw or bayonet system, so that even if a force acts in a direction that causes the housing and the cap to repel each other due to the watertight structure of the filtration membrane, the housing can be attached by simply pressing the housing against the cap and turning it. Moreover, once turning begins, the housing will not come off due to the screw or bayonet structure, so there is no need to press it while turning. Therefore, the work can be done by one person, and the housing and the cap can be attached without using tools. The same applies to removal.

[0016] Furthermore, since the membrane fixing portion and the filtration membrane can be removed at the same time as the housing is removed, the filtration membrane including the membrane fixing portion can be taken out from the cap at the same time by simply removing the housing. In other words, the housing containing the filtration membrane can be removed by slightly separating the housing from the cap by an amount corresponding to the height of the screw or the amount of movement of the bayonet. Therefore, even if the membrane module is installed in a narrow space, the housing containing the filtration membrane can be easily removed.

[0017] Furthermore, if the filtration membrane and the membrane fixing portion are removed from the housing together with the membrane fixing portion, the entire filtration membrane can be exposed and washed. Since the membrane fixing part and the fixed filtration membrane can be removed from the housing after it has been removed from the cap so that the entire filtration membrane is exposed, the filtration membrane can be manually cleaned, for example, by spraying it with water from a hose or by immersing it in stored cleaning water. Therefore, the filtration membrane can be cleaned in a simple manner without using backwashing or bubbling, which requires a control device.

[0018] Among the means that can be adopted to solve the problem, the following means can also be used. As one of the membrane modules in another embodiment, the housing can be configured so that the inside can be viewed. The phrase "the interior is visible" means that a means is provided that allows the interior condition to be visually confirmed from at least a portion of the housing.

[0019] In this configuration, by providing a housing configured so that the inside can be visually confirmed, it is possible to check the state of impurities deposited on the internal membrane module. Therefore, there is no need to stop the filtration operation and remove the housing to check when to clean the filtration membrane. This allows even those with little knowledge or experience to determine the need to clean the filtration membrane without significantly reducing filtration efficiency.

[0020] As yet another means that can be adopted to solve the problem, a membrane filtration device can be adopted for obtaining secondary treated water from impurity-containing water to be treated by removing the impurities. The basic configuration of the membrane filtration device includes an external pressure type hollow fiber membrane module, a pump for sucking the primary treated water filtered by the hollow fiber membrane module, and a reverse osmosis membrane module using a reverse osmosis membrane for filtering the primary treated water to obtain secondary treated water.

[0021] Here, the external pressure type hollow fiber membrane module is configured to include a membrane fixing portion for fixing an end of a filtration membrane, a housing for accommodating the filtration membrane, and a cap for removably fixing the housing. The housing is detachable from the cap by a screw or bayonet, and the membrane fixing part and the filtration membrane can be removed at the same time as the housing is removed. By removing the filtration membrane and the membrane fixing part from the housing, the entire filtration membrane can be exposed. The housing may be configured so that the inside thereof is visible.

[0022] In the above hollow fiber membrane module, the housing is detachably disposed vertically and spaced apart from the ground. By disposing the hollow fiber membrane module vertically, it is possible to prevent the water remaining in the housing from spilling out and contaminating the surroundings when the housing is removed from the cap.

[0023] Moreover, the reverse osmosis membrane module is disposed parallel (horizontally) to the ground. By arranging the reverse osmosis membrane module horizontally, when connecting multiple reverse osmosis membrane modules in series depending on the salinity of the water to be treated, it only needs to be extended in the length direction, which does not require working at height compared to when it is extended in the height direction, making the work safer and easier.

[0024] In this configuration, it is also possible to further include a water-to-be-treated suction means for supplying the water to be treated to the membrane module. The untreated water suction means includes a suction pump that sucks the untreated water from a water storage section, and a suction membrane module that is immersed in the water storage section. The water storage portion refers to a reservoir, a river, a well, etc., in which the water to be treated is stored.

[0025] By immersing the suction membrane module in the water storage section and using a suction pump to suck in the water to be treated and send it to the external pressure type membrane module, impurities such as fallen leaves and coarse-grained suspended solids that would block an external pressure type filtration membrane in a short period of time can be removed in advance. In addition, since the suction membrane module is configured to be immersible in the water storage section, if the filtration membrane of the suction membrane module becomes clogged, it can be removed from the water storage section and easily cleaned by spraying water or replaced.

[0026] In this configuration, the hollow fiber membrane modules may be arranged in at least two rows, and at least two rows of the reverse osmosis membrane modules may be arranged with the hollow fiber membrane modules in between.

[0027] By arranging the reverse osmosis membrane modules in at least two rows, even if it is necessary to stop the filtration operation of one reverse osmosis membrane module, filtration can be performed by the other reverse osmosis membrane module, so the filtration membrane can be cleaned without stopping the entire filtration operation.

[0028] In addition, when reverse osmosis membrane modules are arranged horizontally in at least two rows, the piping must be branched and connected. The branched piping must be connected at the same distance to the two rows of reverse osmosis membrane modules to ensure the same pressure drop. In this case, the two rows of reverse osmosis membrane modules are spaced apart by the distance of the branched pipes. Therefore, in the present invention, a hollow fiber membrane module is arranged vertically in this spaced apart portion, that is, at least two rows of reverse osmosis membrane modules are arranged with the hollow fiber membrane module sandwiched therebetween. This makes the pressure of the water flowing into each opposing reverse osmosis membrane module uniform, and also makes effective use of dead space, allowing the entire membrane filtration device to be made compact.

[0029] As yet another means that can be adopted to solve the problem, it is also possible to provide a configuration in which, when switching the flow paths in the membrane filtration device, no solenoid valves are provided, and only manual valves are provided. By using only manual valves and not using solenoid valves, a control device is not required, and manufacturing costs can be reduced. Even if solenoid valves are not provided, the housing can be removed and washed manually instead of backwashing or bubbling, so that the flow path can be easily switched and washed by simply switching the manual valve when cleaning. Effect of the Invention

[0030] In the membrane module of the present invention, the housing is configured to be detachable from the cap using a screw or bayonet system, so that the installation and removal can be easily performed by one person. Furthermore, the membrane fixing part and the filtration membrane can be removed at the same time as the housing is removed, so that even if the membrane module is installed in a narrow space, the housing can be removed with the minimum necessary movements. Then, the filtration membrane and the membrane fixing portion can be removed from the housing to expose the entire filtration membrane.

[0031] These actions enable even a person lacking specialized knowledge or experience to easily remove and clean the filtration membrane as needed, and also result in a membrane module that is not easily damaged even if the filtration membrane is repeatedly attached and detached.

[0032] In addition, in a membrane filtration device using the membrane module of the present invention as a hollow fiber membrane module, the hollow fiber membrane module is arranged vertically with the housing detachably separated from the ground, and the reverse osmosis membrane module is arranged horizontally. The vertical orientation of the hollow fiber membrane modules allows for easy removal of the housing, and cleaning is done manually, eliminating the need for pumps and controls for backwashing. Furthermore, by arranging the reverse osmosis membrane module horizontally, when multiple reverse osmosis membrane modules are connected in series as necessary, it becomes easier to replace the filtration membrane, and other operations become easier.

[0033] These actions provide the advantage that the membrane filtration device can be manufactured at low cost and has excellent maintainability. [Brief description of the drawings]

[0034] [Figure 1] FIG. 1 is a cross-sectional view showing a membrane module of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram showing a state in which a filtration membrane is removed from a membrane module of the present invention. [Diagram 3]FIG. 2 is an explanatory diagram showing a state in which the filtration membrane of the membrane module of the present invention is washed. [Figure 4] FIG. 1 is a schematic diagram showing a membrane filtration device using a membrane module of the present invention. [Diagram 5] FIG. 2 is a cross-sectional view showing a membrane module according to a first modified example of the present invention. [Figure 6] FIG. 11 is a schematic diagram showing a membrane filtration device in Modification 2 of the present invention. [Figure 7] FIG. 1 is a cross-sectional view showing a conventional example of Patent Document 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the following description, the figures are depicted diagrammatically for the sake of simplicity. For example, the hollow fiber membranes 1·1... are actually bundled together in numbers of tens to hundreds, but for simplification, they are shown in the figures as only a few.

[0036] The membrane module 100 of the present invention is a hollow fiber membrane module using the so-called external pressure total flow filtration method, and as shown in Fig. 1, includes hollow fiber membranes 1·1... which are filtration membranes and are formed by bundling a plurality of hollow fibers, a membrane fixing part 2 adhesively fixed to one end 11 of the hollow fiber membranes 1·1..., a housing 3 that accommodates the hollow fiber membranes 1·1... and the membrane fixing part 2 in an insertable and removable manner, and a cap 4 that can attach and detach the housing 3 by screwing or bayonet. The filtration method may be a cross-flow method.

[0037] In the present invention, it is sufficient to have at least the above-mentioned components, and other components may also be included. For example, in the embodiment shown in Fig. 1, a sealing and fixing part 5 that seals and fixes the other ends 12 of the hollow fiber membranes 1·1... is provided, but the hollow fiber membranes 1·1... may be folded back in a U-shape and both ends of the hollow fiber membranes 1·1... may be fixed by membrane fixing parts 2.

[0038] The hollow fiber membrane 1 is a cylindrical filtration membrane, and can be made of synthetic resins such as PVDF (polyvinylidene fluoride), polyethylene, polypropylene, etc., but can also be made of fine ceramics using inorganic materials such as alumina, titania, zirconia, etc. The diameter, length, total membrane area, and number of hollow fiber membranes 1 can be appropriately selected depending on the scale of the device. Furthermore, the hollow fiber membrane 1 can be selected from a microfiltration membrane (MF membrane), an ultrafiltration membrane (UF membrane), and a nanofiltration membrane (NF membrane) depending on the size of the object to be separated.

[0039] The membrane fixing part 2 fixes the bundled hollow fiber membranes 1, and serves to separate water in contact with the surface of the hollow fiber membranes 1 from water that has passed through the hollow parts of the hollow fiber membranes 1 in a watertight manner. For example, when filtration is performed by external pressure, the water to be treated passes from the surface of the hollow fiber membrane 1 toward the hollow part. At this time, impurities cannot pass through the micropores of the hollow fiber membrane 1, but water can, so the filtered treated water can be taken out from the hollow part of the hollow fiber membrane 1. At this time, the membrane fixing part 2 provides a watertight partition between the cap 4 and the water to be treated so that the filtered treated water does not mix with each other.

[0040] The housing 3 houses the hollow fiber membranes 1·1... and the membrane fixing part 2, and also serves to store the water to be treated inside the housing 3 and immerse the hollow fiber membranes 1·1... in the water to be treated. The housing 3 is a container made of, for example, synthetic resin or metal, and can have various shapes, but in the embodiment in Fig. 1, it is cylindrical for ease of attachment and detachment, which will be described later. In addition, since the embodiment shown in FIG. 1 employs a dead-end filtration system, the housing 3 has a simple container shape. However, if a cross-flow system is employed, the housing 3 may be configured to be connected to a drain for discharging concentrated water.

[0041] When the housing 3 is made of synthetic resin, it is preferable to configure it so that the inside can be seen. For example, in the embodiment shown in Fig. 1, the entire housing 3 is made of colorless and transparent resin. Alternatively, a transparent window may be provided in a part of the housing. In this way, by making the interior visible, it is possible to visually check the degree of accumulation of impurities on the hollow fiber membranes 1·1... as the filtration operation continues, and to know when it is time to clean them in an easier way than by electrically detecting a decrease in filtration performance.

[0042] As described above, the membrane fixing part 2 provides a watertight partition so that the water to be treated and the treated water do not mix. When the hollow fiber membranes 1·1... and the membrane fixing part 2 are housed inside the housing 3 and the cap 4 is fastened, the outer periphery of the membrane fixing part 2 and the inner periphery of the cap 4 form a watertight structure. For example, as shown in Fig. 1, the membrane fixing part 2 can be formed hollow and its inside can be configured to communicate with the inner periphery of the hollow fiber membrane 1.

[0043] The housing 3 is configured so that, with the hollow fiber membranes 1·1 . . . and the membrane fixing part 2 housed therein, it can be detachably attached to a cap 4 by a screw or bayonet method. The cap 4 is provided with a plurality of nozzles 41, 42... for connection to piping. For example, a treated water nozzle 41 for introducing the treated water into the housing 3 and a treated water nozzle 42 for extracting the treated water filtered by the hollow fiber membranes 1, 1... and sending it to the outside are provided.

[0044] The cap 4 can be easily attached and detached by rotating it a predetermined angle relative to the housing 3 using a screw or bayonet system. With the cap 4 attached to the housing 3, the central communication part 21 provided in the center of the membrane fixing part 2 is in close contact with the tip of the treated water nozzle 42. As a result, the treated water extracted from the hollow parts of the hollow fiber membranes 1·1... is temporarily stored in the space formed within the membrane fixing part 2 and is sent to the outside by the treated water nozzle 42.

[0045] Furthermore, the water to be treated introduced into the housing 3 from the nozzle 41 for the water to be treated is introduced into the housing 3 through the outer circumferential communicating part 22 of the membrane fixing part 2 without being mixed with the treated water. For example, by arranging the outer circumferential communicating parts 22 on a circumference of the same diameter, even if the cap 4 is attached by a screw or bayonet method, the outer circumferential communicating parts 22 do not hinder the rotational movement of the cap 4, and the water to be treated can be introduced into the housing 3 without being mixed with the treated water in the cap 4.

[0046] When polluted water to be treated is filtered using the membrane module 100 configured as described above, impurities accumulate on the surfaces of the hollow fiber membranes 1·1..., decreasing the filtration efficiency. As shown in Fig. 1, the housing 3 is configured so that the inside can be seen, so that the state of impurities accumulated on the hollow fiber membranes 1·1... can be visually confirmed. Therefore, when it is determined by visual inspection that it is time to clean the membranes, cleaning is performed.

[0047] There are various methods for cleaning the hollow fiber membranes 1·1..., including physical methods such as backwashing and chemical methods using cleaning agents. In the present invention, however, cleaning is performed by a physical method, such as manual water spraying, without backwashing. First, the housing 3 is removed from the cap 4. The cap 4 is in a fixed state with the treated water nozzle 41 and the treated water nozzle 42 connected to piping (not shown). Therefore, when removing the housing 3, as shown in Fig. 2(a), the housing 3 is grasped with both hands and rotated in a predetermined direction. If a screw type is used, it is rotated several times, and if a bayonet type is used, it is rotated by a predetermined angle of 180 degrees or less.

[0048] When the housing 3 is rotated to a state where it can be separated from the cap 4, it is pulled out in the longitudinal direction as shown in Fig. 2(b) . At this time, the housing 3 is pulled out while the hollow fiber membranes 1·1... and the membrane fixing part 2 are housed inside the housing 3. 2(c), the hollow fiber membranes 1·1... and the membrane fixing part 2 are pulled out and removed from the housing 3. When pulling out, the membrane fixing part 2 is grasped and pulled out, so providing a gripping part on the membrane fixing part 2 makes the work easier.

[0049] When pulled out, the hollow fiber membranes 1·1... are entirely exposed, as shown in Fig. 3. In this state, impurities deposited on the surfaces of the hollow fiber membranes 1·1... can be removed by spraying water from a hose or by hand-washing the membrane by immersing it in stored water. Incidentally, impurities peeled off from the surfaces of the hollow fiber membranes 1·1... adhere to and accumulate inside the housing 3. Therefore, it is advisable to also wash the inside of the housing 3 by a method such as spraying water.

[0050] After the hollow fiber membranes 1·1 . . . have been washed by the above-mentioned method, the hollow fiber membranes 1·1 . In this way, the membrane module 100 of the present invention can be cleaned only by manual labor without using a cleaning method such as backwashing that requires a control device, and no special tools are required to attach and detach each member for cleaning. Therefore, even a person without specialized knowledge or experience can perform filtration while performing continuous maintenance by periodically cleaning the filtration membrane. In addition, since no external force is applied to the hollow fiber membranes 1.1... during the process of removing, cleaning, and then reinstalling them, the hollow fiber membranes 1.1... are unlikely to be damaged. Therefore, the hollow fiber membranes 1.1... are unlikely to be damaged even if they are repeatedly removed and attached.

[0051] Here, a membrane filtration device 200 using the above-mentioned membrane module 100 will be described with reference to FIG. As shown in FIG. 4, the membrane filtration apparatus 200 of the present invention includes the above-mentioned hollow fiber membrane modules 100 / 100' arranged in two rows, a pump 210 for sucking the primary treated water filtered by the hollow fiber membrane modules, reverse osmosis membrane modules 220 / 220' using reverse osmosis membranes for filtering the primary treated water to obtain secondary treated water, and treated water suction means 250 for supplying the treated water to the hollow fiber membrane modules 100 / 100'. In the embodiment shown in FIG. 4, the hollow fiber membrane module 100 is of a dead-end filtration type, and the reverse osmosis membrane module 220 is of a cross-flow type.

[0052] The hollow fiber membrane modules 100 and 100' are arranged vertically in two rows, and the bottom surfaces of the housings 3 and 3' are spaced apart from the ground so that they can be detached. In other words, they are arranged so as to be suspended from a stand (not shown) with the caps 4 and 4' as fixing parts. The reverse osmosis membrane modules 220 / 220' are arranged horizontally, sandwiching the hollow fiber membrane modules 100 / 100'. In the embodiment in Fig. 4, the reverse osmosis membrane modules 220 / 220' are arranged close to the bottom side of the hollow fiber membrane modules 100 / 100' (closer to the ground in the height direction), but the position in the height direction is not limited to this, and they may be arranged closer to the top.

[0053] The treated water suction means 250 has a suction pump 251 connected to the hollow fiber membrane module 100, and a suction membrane module 252 connected to the tip of the suction pump 251. The suction pump 251 and the suction membrane module 252 are each connected by a flexible suction hose 253.

[0054] The suction membrane module 252 is dropped into a reservoir pond or a well that stores groundwater and is immersed in the reservoir. The reservoir contains impurities such as coarse suspended matter and fallen leaves, and if the water is sent directly to the hollow fiber membrane module 100, the hollow fiber membranes of the hollow fiber membrane module 100 will become clogged in a short period of time, resulting in extremely poor filtration efficiency. Therefore, the water to be treated is sucked through the suction membrane module 252 to remove impurities such as suspended matter and fallen leaves to a certain extent in advance.

[0055] Here, it is conceivable that the suction membrane module 252 will also become clogged in a short period of time. However, unlike the fixed hollow fiber membrane modules 100 / 100', the suction membrane module 252 can be pulled out of the water storage section by pulling the flexible suction hose 253, and therefore the suction membrane module 252 can be easily cleaned or replaced.

[0056] The overall filtration configuration is as follows: first, the water to be treated is pumped by a suction pump 251 through a suction membrane module 252 to the hollow fiber membrane modules 100 / 100'. The hollow fiber membrane modules 100 / 100' then remove suspended solids, which are a type of impurity, to obtain clear primary treated water. However, simply removing the suspended solids leaves residual chromaticity components, bacteria, viruses, salt, and other ionic components. Therefore, by further using reverse osmosis membrane modules 220 / 220', these remaining components can be removed to obtain colorless, transparent secondary treated water suitable for drinking.

[0057] In the embodiment shown in Fig. 4, the pump 210 is provided between the hollow fiber membrane modules 100 / 100' and the reverse osmosis membrane modules 220 / 220'. In other words, the pump 210 sucks the primary treated water obtained from the hollow fiber membrane modules 100 / 100' and sends the sucked primary treated water to the reverse osmosis membrane modules 220 / 220' to enable cross-flow filtration. When the hollow fiber membrane module 100 is of a cross-flow type, another pump may be provided to send the water to be treated to the hollow fiber membrane module 100.

[0058] Moreover, each member is connected by a pipe 230. First, a water-to-be-treated pipe 231 for supplying the water to be treated from a suction pump 251 is connected to the water-to-be-treated nozzle 41 in the cap 4 of one of the hollow fiber membrane modules 100.

[0059] The treated water nozzle 42 in the cap 4 of one hollow fiber membrane module 100 is connected to the treated water nozzle 41' of the other hollow fiber membrane module 100', so that the treated water from one hollow fiber membrane module 100 is introduced as the treated water into the other hollow fiber membrane module 100'. That is, filtration is performed in two stages. Note that the filtration by the hollow fiber membrane module 100 does not necessarily need to be in two stages, and it may be in one stage or three or more stages.

[0060] Next, the treated water nozzle 42' of the second-stage hollow fiber membrane module 100' and the inlet of the pump 210 are connected by a pump inlet pipe 232, and the outlet of the pump 210 is connected to a pump outlet pipe 233 for introducing the primary treated water into the reverse osmosis membrane modules 220 / 220'. Here, the pump delivery pipe 233 branches into two at a branch point 236 midway, and these are connected to the reverse osmosis membrane modules 220 and 220' at equal distances.

[0061] Finally, connected to the reverse osmosis membrane modules 220 / 220' are secondary treatment water pipes 234 / 234' for discharging filtered secondary treatment water, and concentrated water pipes 235 / 235' for discharging concentrated water with an increased concentration of impurities. Those who wish to use the secondary treated water as drinking water or the like can obtain the secondary treated water by operating a valve installed in the pipe where the secondary treated water pipes 234 and 234' join together.

[0062] Each pipe 230 is provided with an appropriate manual valve with a lever 240. For example, the concentrated water pipes 235 and 235' are provided with concentrated water manual valves 241 and 241' for switching between cross-flow filtration and flushing and for adjusting the flow rate of filtration.

[0063] In the embodiment shown in FIG. 4, the hollow fiber membrane modules 100, 100' are arranged vertically, with the bottom surfaces of the housings 3, 3' spaced a predetermined distance from the ground. By arranging the housing 3 so as to be suspended above the ground in this manner, the housing 3 can be removed and separated from the membrane filtration device 200 during cleaning.

[0064] As described above, the housing 3 can be removed from the cap 4 while accommodating the hollow fiber membranes 1·1... and the membrane fixing part 2, so even if the hollow fiber membrane 1 is long, it can be removed from the cap 4 by moving it in parallel only a small distance. In other words, it is only necessary to keep it away from the ground by that amount of movement, so the entire device can be made compact.

[0065] Furthermore, by arranging the reverse osmosis membrane modules 220 / 220' close to the bottom side of the hollow fiber membrane modules 100 / 100', the center of gravity of the entire device can be made low. In addition, when removing the housings 3 / 3' of the hollow fiber membranes 100 / 100, a large space can be secured around the housings 3 / 3', making it easy to insert hands into the housings 3 / 3' without the reverse osmosis membrane modules 220 / 220' interfering with the work.

[0066] Furthermore, by arranging the reverse osmosis membrane modules 220 and 220' sideways, the center of gravity can be kept low and work is easy even when other reverse osmosis membrane modules are added in series as needed. In addition, the reverse osmosis membrane itself can be easily removed from the vessel when replacing it.

[0067] The reverse osmosis membrane modules 220 / 220' are arranged so that the hollow fiber membrane modules 100 / 100' are placed in the gap between the reverse osmosis membrane modules 220 / 220 created by branching at the branching section 236. In other words, the reverse osmosis membrane modules 220 / 220' are arranged to sandwich the hollow fiber membrane modules 100 / 100'. This makes it possible to effectively utilize the gap created by the branching section 236 and to configure the entire membrane filtration device 200 compactly.

[0068] Even in this case, since the reverse osmosis membrane modules 220 / 220' are positioned close to the bottom side of the hollow fiber membrane modules 100 / 100', a large space can be secured around the housings 3 / 3' when removing the housings 3 / 3' of the hollow fiber membranes 100 / 100, making it easy to insert hands into the housings 3 / 3' without the reverse osmosis membrane modules 220 / 220' obstructing the work.

[0069] If the filtration operation continues, impurities will accumulate on the reverse osmosis membrane of the reverse osmosis membrane module 220, reducing the filtration efficiency. In this case, the reverse osmosis membrane module 220 is cleaned by fully opening the concentrated water pipe 245 to perform flushing or by mixing a cleaning agent into the water introduced therein.

[0070] As described above, in the membrane module 100 of the present invention and the membrane filtration device 200 using the same, even a person lacking in specialized knowledge or experience can easily remove and clean the hollow fiber membrane 1 as needed, and the hollow fiber membrane 1 is not easily damaged even if it is repeatedly attached and detached. In addition, since the hollow fiber membrane module 100 is oriented vertically, the housing 3 can be easily removed and cleaned manually, eliminating the need for pumps and control devices required for backwashing, resulting in low manufacturing costs and excellent maintainability.

[0071] 『Variation 1』 Next, a membrane module 101 according to a modified example of the present invention will be described with reference to Fig. 5. In the following description, the same parts are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0072] This modified example differs from the embodiment shown in FIG. 1 in that a concentrated water outlet 31 is provided in the housing 3 to implement a cross-flow system. 1, in this modification, the water to be treated is supplied through a water to be treated nozzle 42 provided in the cap 4, and passes through a duct inside the housing 3 and flows into the housing 3 from near the lower ends of the hollow fiber membranes 1·1.... In other words, the water to be treated flows from the bottom to the top. Therefore, in this modification, the concentrated water outlet 31 is provided at the upper part of the housing 3.

[0073] Furthermore, when cleaning, the housing 3 must be removed from the cap 4 and the piping connected to the concentrated water outlet 31 must be disconnected. Therefore, by providing a manual valve (not shown) on the housing 3 side of the concentrated water discharge port 31, it is possible to prevent the water to be treated stored in the housing 3 from flowing out of the concentrated water discharge port and polluting the surrounding area. It is preferable that the connecting piping be made easily detachable by using a one-touch joint or the like.

[0074] With the above-mentioned configuration, even in the case of the membrane module 101 employing the cross-flow system as in this modified example, the filtration membrane 1 can be removed from the membrane module 101 and washed manually.

[0075] 『Variation 2』 Next, a membrane filtration device 201 according to another modified example of the present invention will be described with reference to FIG. This modification differs from the embodiment in FIG. 4 in that two hollow fiber membrane modules 100, 100' are arranged in parallel rather than in series.

[0076] More specifically, the treated water pipe 231 branches into two at a branching point 236', and is connected to one hollow fiber membrane module 100 and the other hollow fiber membrane module 100', respectively. Furthermore, manual treated water valves 242 and 242' with levers are provided at the ends of the branches, allowing the flow of the treated water to be switched between the respective pipes.

[0077] In this modified example, filtration is normally performed by the two hollow fiber membrane modules 100, 100' with both of the manual valves for water to be treated 242, 242' open. When impurities accumulate in one or both of the hollow fiber membranes 1, 1... and the filtration efficiency decreases, first one of the manual valves for water to be treated 242, 242' is closed.

[0078] Then, the hollow fiber membranes of one of the hollow fiber membrane modules connected to the closed valve are cleaned. At this time, the other hollow fiber membrane module connected to the open valve continues filtration. Therefore, by arranging the hollow fiber membrane modules 100 and 100' in parallel, for example, even while one hollow fiber membrane module 100 is being cleaned, filtration can be continued in the other hollow fiber membrane module 100'. This makes it possible to eliminate the time during which the secondary treated water cannot be used due to the suspension of filtration. Note that the hollow fiber membrane modules may be arranged in parallel, and then each of the modules may be further connected in series.

[0079] The present invention is not limited to the above-described embodiment. For example, a compressor may be connected to the water-to-be-treated pipe 231 so that air can be manually blown into the hollow fiber membrane modules 100 / 100'. [Explanation of symbols]

[0080] 100,101 Hollow fiber membrane module 1. Hollow fiber membrane 11 one end 12 Other end 2 Membrane fixing part 21 Center communication part 22 Outer periphery connection part 3. Housing 31 Concentrated water outlet 4 Cap 41 Treated water nozzle 42 Treated water nozzle 5 Sealing fixing part 200,201 Membrane filtration equipment 210 Pump 220 Reverse Osmosis Membrane Module 221 Internal pressure type membrane filtration device 222 Activated carbon charging device 230 Piping 231 Treated water piping 232 Pump inlet piping 233 Pump delivery piping 234 Secondary treated water piping 235 Concentrated water piping 236 Branch 240 Manual valve 241 Concentrated water manual valve 242 Manual valve for treated water 250 Means for suctioning water to be treated 251 Suction Pump 252 Suction Membrane Module 253 Suction Hose

Claims

1. A membrane module including a filtration membrane for removing impurities from treated water containing impurities, The present invention includes a membrane fixing part for fixing an end of the filtration membrane, a housing for accommodating the filtration membrane, and a cap for removably fixing the housing, The housing is detachable from the cap by a screw or bayonet method, and the membrane fixing part and the filtration membrane can be simultaneously removed when the housing is removed; A membrane module, characterized in that the entire filtration membrane can be exposed by removing the filtration membrane and the membrane fixing part from the housing.

2. 2. The membrane module according to claim 1, wherein the housing is configured so that the inside thereof can be visually observed.

3. A membrane filtration apparatus for obtaining secondary treated water by removing impurities from treated water containing the impurities, The membrane module according to claim 1 or 2, comprising: an external pressure type hollow fiber membrane module; a pump for sucking primary treated water filtered by the hollow fiber membrane module; and a reverse osmosis membrane module using a reverse osmosis membrane for filtering the primary treated water to obtain secondary treated water; The hollow fiber membrane module is disposed vertically with the housing detachably spaced from the ground, A membrane filtration apparatus, wherein the reverse osmosis membrane module is arranged horizontally.

4. The system further includes a water-to-be-treated suction means for supplying the water to be treated to the membrane module, 4. The membrane filtration device according to claim 3, wherein the untreated water suction means comprises a suction pump that sucks the untreated water from a water storage section, and a suction membrane module that is immersed in the water storage section.

5. The hollow fiber membrane modules are arranged in at least two rows, 5. The membrane filtration device according to claim 4, wherein at least two rows of the reverse osmosis membrane modules are arranged horizontally with the hollow fiber membrane module in between.

6. 4. The membrane filtration device according to claim 3, wherein in switching the flow path, no solenoid valve is provided, and only a manual valve is provided.

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