JP2014147919A - Membrane filtration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane filtration system in which a membrane filter can be effectively performed by back wash by a simple configuration.SOLUTION: A membrane filtration system includes: a columnar membrane filter that includes a water passing pore that extends in an axial direction between both edge faces and a separation layer that positions in a periphery of the water passing pore; and a filtration apparatus that includes a container in which the membrane filter is accommodated in an interior space and in which water to be treated that is supplied into the water passing pore of the membrane filter is filtered by a separation layer to obtain filtered water, and the membrane filtration system is characterized in that the container that accommodates the membrane filter is disposed to turn an axis line of the membrane filter in a substantially vertical direction, the interior space of the container is divided to a primary side region in which the water to be treated flows and a secondary side region in which the filtered water flows, and a back wash mechanism in which a pressurization gas is used to compress the filtered water that exists in the secondary side region, the compressed filtered water is made to inflow to the primary side region, thereby the membrane filter is performed by back wash; and a spacer that is disposed between an upper edge face of the membrane filter and an upper edge face of the interior space, and has a small diameter than that of the interior space are further included.

Description

  The present invention relates to a membrane filtration system, and more particularly to a membrane filtration system capable of effectively backwashing a filtration membrane with a simple configuration.

  In general, water using membrane filtration is a method for separating and removing pollutants in water to be treated in various water treatment systems such as water treatment systems, sewage treatment systems, industrial water treatment systems, wastewater treatment systems, and seawater desalination systems. Processing methods are known.

  Here, in the water treatment method using membrane filtration, as filtration continues, contaminants in the water to be treated adhere to the filtration membrane, resulting in clogging (fouling) of the filtration membrane, resulting in a decrease in filtration performance ( Therefore, it is necessary to regularly clean the filtration membrane by backwashing (hereinafter referred to as “backwashing”) to eliminate clogging.

  Therefore, conventionally, in a membrane filtration system that filters treated water using a filtration membrane, backwash water is periodically passed from the secondary side (filtrated water side) of the filtration membrane to the primary side (treated water side). The filter membrane is backwashed with water. Specifically, in the conventional membrane filtration system, the filtered water obtained by filtering the water to be treated is used as backwash water, and the filtered water is passed through the filtration membrane using a backwash pump. Alternatively, the filtration membrane is backwashed by pressurizing the filtered water stored in the backwash water tank with air or the like and passing the filtrate through the filtration membrane (for example, refer to Patent Documents 1 and 2).

JP 2004-249204 A JP 2011-183320 A

  However, in membrane filtration systems that perform backwashing using a backwash pump or membrane filtration systems that perform backwashing by pressurizing the filtrate stored in the backwash water tank with air, etc., backwash water used for backwashing A backwash water tank for storing (filtered water, etc.) was required. Therefore, the conventional membrane filtration system has room for improvement in that the configuration is simplified by eliminating the need for a backwash water tank.

  Then, this inventor earnestly examined for the purpose of making a backwash water tank unnecessary. And this inventor is the volume (henceforth a "secondary side area | region") of the capacity | capacitance of the container which accommodates the filtration membrane, especially the area | region located in the secondary side of the filtration membrane in a container. By adjusting the volume, it is possible to store the amount of filtered water necessary for backwashing the filtration membrane in the secondary side region. During backwashing, the water in the secondary side region is pressurized with air and filtered. The idea was to backwash the filtration membrane by passing water through the membrane. Thus, if backwashing is carried out using the water in the secondary region, a backwashing water tank can be dispensed with.

  Here, as the filtration membrane, for example, a monolithic ceramic membrane 30 having a lotus root-like water passage hole 31 into which water to be treated flows, as shown in FIG. is there. In the monolithic ceramic membrane 30 having the lotus root-shaped water passage holes 31, for example, the water to be treated that has flowed into the water passage holes 31 is filtered through a separation layer (not shown) located on the surface of each water passage hole 31. The filtered water flows out from the outer peripheral surface 32.

However, in a membrane filtration system using a columnar filtration membrane having a water passage extending between both end faces, such as a monolithic ceramic membrane, and a separation layer located on the surface of the water passage. The present inventor has further investigated the fact that the amount of filtered water necessary for backwashing of the membrane is secured in the secondary region, and the filtered water in the secondary region is pressurized with air or the like for backwashing. As a result, it became clear that the following problems occur in the membrane filtration system using the columnar filtration membrane with the inside of the water passage hole as the primary side.
That is, as shown in FIG. 7 (a), a columnar filtration membrane 92 having a water passage hole 91 and a separation layer is accommodated in a container 93 having an internal space with a length substantially equal to the filtration membrane 92, When the water passage hole 91 is vertically placed so that the extending direction of the water passage hole 91 is substantially perpendicular to the installation surface, when the filtrate in the secondary region 94 is pressurized with air or the like and backwashed, FIG. As shown in (b), since the water level of the filtrate in the secondary region 94 decreases with time, it has become clear that there is a problem that the upper part of the filter membrane 92 cannot be sufficiently washed.

  Therefore, the present invention is a membrane filtration system using a columnar filtration membrane having a water passage hole and a separation layer located on the surface of the water passage hole, and effectively backwashes the filtration membrane with a simple configuration. The object is to provide a possible membrane filtration system.

An object of the present invention is to advantageously solve the above-described problem, and the membrane filtration system of the present invention is provided with a water passage hole extending in the axial direction between both end faces and around the water passage hole. A columnar filtration membrane having a separation layer, and a container in which the filtration membrane is accommodated in an internal space, and the treated water supplied into the water passage holes of the filtration membrane is filtered through the separation layer. A membrane filtration system comprising a filtration device for obtaining filtered water, wherein the container containing the filtration membrane is installed with the axis of the filtration membrane oriented in a substantially vertical direction, and the internal space of the vessel is the water to be treated Is divided into a primary side region through which the filtered water flows and a secondary side region through which the filtered water flows, pressurizing the filtered water present in the secondary side region using a pressurized gas, Backwashing mechanism for backwashing the filtration membrane by flowing into the side region, and It disposed between the upper end surface and the upper end surface of the inner space of the filtration membrane, and further comprising a small diameter spacer than the internal space. Thus, if the filtered water which exists in a secondary side area | region is pressurized with pressurized gas and used for backwashing, the structure of a membrane filtration system can be simplified by making a backwash water tank unnecessary. In addition, if a spacer having a smaller diameter than the internal space is provided on the upper part of the filtration membrane, even when backwashing is performed using a pressurized gas, the water level starts from the portion around the spacer in the secondary region. descend. Therefore, at the initial stage of backwashing, the filtration membrane can be backwashed in the presence of filtrate water around the filtration membrane, so that the entire filtration membrane can be backwashed effectively.
In the present invention, the “substantially vertical direction” includes a direction inclined with respect to the vertical direction within a range in which the effect of the present invention is obtained, for example, a direction having an angle of 15 ° or less with respect to the vertical direction. And, in the present invention, “install the filtration membrane with the axis of the membrane oriented substantially vertically” means that the membrane is installed so that the axis of the membrane extends along the vertical direction, and within the range where the effects of the invention can be obtained. And installing so that the axis of the filtration membrane extends at an angle of, for example, 15 ° or less with respect to the vertical direction.

  Here, in the membrane filtration system of the present invention, the backwash mechanism causes the pressurized filtered water to flow into the primary region in a plurality of times and to flow into the primary region at least for the first time. The amount is preferably equal to or less than the amount of filtered water present between the outer peripheral surface of the spacer and the inner peripheral surface of the container facing the spacer. If the pressurized filtered water is divided into a plurality of times and allowed to flow into the primary region, and at least the first inflow is less than the amount of filtered water existing between the spacer and the inner peripheral surface of the container, the secondary side The water level of the filtered water in the region does not drop to the upper end position of the filtration membrane during the first water flow. Therefore, the filtered water can be passed through the filter membrane a plurality of times in a state where the pressure is uniformly applied to the outer peripheral surface of the filter membrane, and the entire filter membrane can be backwashed more effectively.

  In the membrane filtration system of the present invention, it is preferable that the spacer has a reduced diameter portion whose outer diameter is smaller than a spacer end portion on the filtration membrane side. If a reduced diameter part is provided in the spacer, the amount of filtered water existing between the outer peripheral surface of the spacer and the inner peripheral surface of the container facing the spacer is increased, and the entire filtration membrane is backwashed more effectively. can do.

  According to the present invention, there is provided a membrane filtration system using a columnar filtration membrane having a water passage hole and a separation layer located on the surface of the water passage hole, and effectively backwashes the filtration membrane with a simple configuration. A possible membrane filtration system can be provided.

It is a figure which shows schematic structure of the typical membrane filtration system according to this invention. It is an expanded sectional view which shows the principal part structure of the container in which the filtration membrane of the membrane filtration system shown in FIG. 1 and the filtration membrane were accommodated, (a) shows the structure of the filtration membrane and the upper part of a container, (b) is filtration. 2 shows the configuration of the membrane and the lower part of the container. (A)-(c) is explanatory drawing explaining the fluctuation | variation of the water level in a secondary side area | region at the time of backwashing a filtration membrane in the membrane filtration system shown in FIG. It is a figure which shows the modification of the spacer of the membrane filtration system shown in FIG. 1 with a filtration membrane and a container. It is a figure which shows schematic structure of the membrane filtration system of a modification. It is explanatory drawing which shows the structure of a monolithic ceramic film | membrane by notching a part of ceramic film | membrane. It is explanatory drawing explaining the fluctuation | variation of the water level in a secondary side area | region at the time of carrying out backwashing of the filtration membrane in the membrane filtration system which accommodated and used the columnar filtration membrane inside the container of the length substantially equal to a filtration membrane. (A) shows the state immediately before the start of backwashing, and (b) shows the state after the start of backwashing.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, what attached | subjected the same code | symbol in each figure shall show the same component.

  The membrane filtration system of the present invention is not particularly limited, when separating and removing pollutants in the water to be treated in various water treatments such as clean water treatment, sewage treatment, industrial water treatment, wastewater treatment, seawater desalination, etc. Can be used.

  Here, in FIG. 1, schematic structure of an example of the membrane filtration system of this invention is shown. A membrane filtration system 100 shown in FIG. 1 includes a treated water tank 10 that stores treated water, and a filtration device that houses a filtration membrane 30 inside a container 20. And in this membrane filtration system 100, the to-be-processed water in the to-be-processed water tank 10 is filtered with the filter membrane 30 of a filtration apparatus, and filtered water is obtained.

The treated water tank 10 is connected to the lower part of the container 20 of the filtration device via the treated water line 11. And the to-be-processed water stored in the to-be-processed water tank 10 is sent into the container 20 using the to-be-processed water pump 12 provided in the to-be-processed water line 11, and is filtered with the filter membrane 30. FIG.
A treated water valve 13 is provided between the treated water pump 12 and the container 20 in the treated water line 11. Further, a backwash drainage line 70 is branched and extended from the treated water line 11 between the treated water valve 13 and the container 20. A backwash drain valve 71 is provided in the backwash drain line 70.

The container 20 is such that the lower end portion of a cylindrical container body is liquid-tightly closed by two partition plates 22 and 23, and the upper end portion of the container body is liquid-tightly closed by two partition plates 25 and 26. is there. Here, a first common flow path 24 is formed between the partition plate 22 and the partition plate 23. A second common flow path 27 is formed between the partition plate 25 and the partition plate 26. The treated water line 11 is connected to the first common flow path 24, and the air blow pressurized air line 80 and the water filling line 82 are connected to the second common flow path 27. Moreover, the filtered water line 50 is connected to the upper part of the container main body.
The filtrate water line 50 is provided with a filtrate water valve 51, the air blow pressurized air line 80 is provided with an air blow pressurized air valve 81, and the water filling line 82 is provided with A water filling valve 83 is provided. Further, a backwashing pressurized air line 60 extends from the filtered water line 50 between the container 20 and the filtered water valve 51, and the backwashing pressurized air line 60 includes a backwashing. A pressurized air valve 61 is provided.

The container 20 is installed so that the axis of the container 20 is parallel to the vertical direction. In the illustrated example, three filtration membranes 30 are accommodated in the internal space 21 of the container 20 (the space between the partition plate 22 and the partition plate 25). More specifically, the internal space 21 accommodates three filtration membranes 30 and spacers 40 attached to the top of each filtration membrane 30 in a liquid-tight manner.
In the membrane filtration system of the present invention, any container that can accommodate the filtration membrane in a liquid-tight manner can be used as the container. Moreover, in the membrane filtration system of this invention, you may install a container so that an axis line may incline with respect to a perpendicular direction.

  Here, as the filtration membrane 30, a filtration membrane having a columnar shape and having a water passage hole extending in the axial direction between both end faces and a separation layer positioned around the water passage hole can be used. Specifically, the filter membrane 30 is not particularly limited, and a ceramic filter membrane as shown in FIG. 6 can be used.

A filtration membrane 30 shown in FIG. 6 has a cylindrical shape, a plurality of water passage holes 31 extending between both end faces in the axial direction, and a separation layer (not shown) positioned on the surface of the water passage hole 31. Is a monolithic ceramic filtration membrane having In the filtration membrane 30, the water to be treated that has flowed into the water passage holes 31 is filtered by the separation layer located on the surface of each water passage hole 31 and flows out from the outer peripheral surface 32.
In the illustrated example, the filtration membrane 30 is installed such that the axis of the filtration membrane 30 is parallel to the vertical direction. That is, in the membrane filtration system 100, the filtration membrane 30 and the container 20 containing the filtration membrane 30 are installed such that the axis of the filtration membrane 30 is parallel to the vertical direction. Incidentally, in the membrane filtration system of the present invention, the filtration membrane may be installed such that the axis is inclined with respect to the vertical direction.

  The spacer 40 is disposed between the upper end surface of the filtration membrane 30 and the upper end surface (partition plate 25 in the illustrated example) of the internal space 21 of the container 20. The outer diameter of the spacer 40 is smaller than the inner diameter of the container 20, that is, the diameter of the inner space 21. The spacer 40 is a water-impermeable member, unlike the filtration membrane 30.

  As shown in FIG. 2A, the spacer 40 has a cylindrical shape with a large diameter portion 41 connected to the filtration membrane 30 and an upper side of the large diameter portion 41 (with the filtration membrane 30 and Is provided with a tapered portion 42 whose outer diameter and inner diameter gradually decrease toward the upper side, and a small-diameter portion 43 located on the upper side of the tapered portion 42. That is, the spacer 40 has a reduced diameter portion (tapered portion 42 and small diameter portion 43) having an outer diameter smaller than the spacer end portion (large diameter portion 41) on the filtration membrane 30 side.

  Here, as shown in FIG. 2A, the connection between the spacer 40 and the filtration membrane 30 is not particularly limited, and the packing 45 is attached to the step formed on the inner peripheral surface of the large-diameter portion 41 of the spacer 40. It can be performed by placing and press-fitting the filtration membrane 30 into the spacer 40. Specifically, a step smaller than the thickness of the packing 45 is formed on the lower end side of the inner peripheral surface of the large-diameter portion 41 of the spacer 40, and the outer peripheral edge of the end surface of the filtration membrane 30 and the filtration membrane 30 are formed in the step. The filtration membrane 30 is press-fitted into the large-diameter portion 41 of the spacer 40 with the substantially annular packing 45 covering the upper end portion of the outer peripheral surface, thereby allowing the inside of the water passage hole 31 of the filtration membrane 30 and the inside of the spacer 40 to communicate with each other. Meanwhile, the spacer 40 and the filtration membrane 30 can be liquid-tightly connected. In addition, as shown to Fig.2 (a), in the part which contacts the outer peripheral surface of the filtration membrane 30 and the inner peripheral surface of the large diameter part 41 of the spacer 40 of the packing 45, the cyclic | annular protrusion for improving a sealing performance is shown. A part may be formed.

  Further, as shown in FIG. 2A, the connection between the spacer 40 and the partition plate 25 is not particularly limited, and an O-ring 46 is provided in an annular recess 44 formed on the outer peripheral surface of the small diameter portion 43 of the spacer 40. It can be performed by arranging and pressing the small diameter portion 43 into the hole formed in the partition plate 25. Thus, by inserting the small-diameter portion 43 into the hole of the partition plate 25 with the O-ring 46 disposed, the spacer 40 and the partition plate 25 are communicated with each other while the inside of the spacer 40 and the second common flow path 27 are communicated. Can be connected in a liquid-tight manner.

  In addition, the connection between the partition plate 22 located on the lower end side of the container 20 and the filtration membrane 30 is not particularly limited, and as shown in FIG. 2B, around the hole formed in the partition plate 22. A step is formed, and the filtration membrane 30 is placed on the step in a state where a substantially annular packing 47 covering the outer peripheral edge of the end surface of the filtration membrane 30 and the lower end of the outer peripheral surface of the filtration membrane 30 is disposed on the step. Can be performed. Thus, by placing the filtration membrane 30 on the hole of the partition plate 22 with the packing 47 disposed, the inside of the water passage hole 31 of the filtration membrane 30 and the inside of the first common flow path 24 are communicated. Meanwhile, the filtration membrane 30 and the partition plate 22 can be liquid-tightly connected.

  That is, the filtration membrane 30 and the spacer 40 that are liquid-tightly connected to each other are liquid-tightly connected to the partition plate 22 and the partition plate 25. Therefore, when the water to be treated is filtered through the water passage hole 31 of the filtration membrane 30, the inner space 21 of the container 20 is separated from the primary side region (flow passage) through which the water to be treated flows by the filtration membrane 30 and the spacer 40. The inside of the water hole 31 and the spacer 40) and the secondary region through which filtered water flows (the portion located on the inner peripheral surface side of the container 20 with respect to the separation layer of the filtration membrane 30).

And in this membrane filtration system 100, when filtering a to-be-processed water and obtaining filtered water, as shown in FIG. 1, the to-be-processed water valve 13 and the filtrate water valve 51 are opened, and the pressurized air for backwashing The water to be treated pump 12 is operated with the valve 61, the backwash drain valve 71, the air blow pressurized air valve 81 and the water filling valve 83 being closed. And the to-be-processed water which flowed in into the water flow hole 31 of the filtration membrane 30 via the to-be-processed water line 11 and the 1st common flow path 24 is filtered with the separation layer (not shown) of the filtration membrane 30. The filtered water filtered through the separation layer and flowing out from the outer peripheral surface of the filtration membrane 30 flows through the secondary region in the container 20 and flows out from the filtered water line 50.
In addition, although the case where the to-be-processed water was dead-end filtered was demonstrated above, in this membrane filtration system 100, you may carry out a crossflow filtration of to-be-processed water.

  Here, if filtration of water to be treated is continued, contaminants and the like in the water to be treated adhere to the filtration membrane, resulting in clogging of the filtration membrane, resulting in a reduction in filtration performance. Therefore, in this membrane filtration system 100, when the differential pressure of the filtration membrane 30 increases to a predetermined value or more every predetermined time, the water valve 13 to be treated, the filtrate water valve 51, the backwash pressurized air line. 60, the backwashing pressurized air valve 61, the backwashing drain line 70, the backwashing drainage valve 71, and the air blow pressurized air valve 81 are used as a backwashing mechanism to backwash the filtration membrane 30. In addition, operation | movement of each valve and pump at the time of backwashing can be controlled using the control apparatus which is not shown in figure.

Specifically, first, as shown in FIG. 3A, the treated water pump 12 is stopped, the treated water valve 13, the filtered water valve 51, the backwash drain valve 71, the pressurized air for air blow. The backwashing pressurized air valve 61 is opened with the valve 81 and the water filling valve 83 closed, and the filtered water present in the secondary region of the container 20 using the backwashing pressurized air as the pressurized gas. Pressurize.
Next, as shown in FIGS. 3 (b) and 3 (c), the backwash drain valve 71 is opened, and the pressurized filtrate in the secondary side region is passed through the water passage hole 31 (primary side region) of the filtration membrane 30. The filter membrane 30 is back-washed by flowing in.
In addition, after the backwashing using the filtered water in the secondary region is completed, the backwashing pressurized air valve 61 is optionally closed, the air blowing pressurized air valve 81 is opened, and the air blowing pressure is increased. The compressed air may be flowed into the water passage hole 31 of the filtration membrane 30 and the inside of the water passage hole 31 may be further washed with pressurized air for air blow. Incidentally, after the cleaning of the filtration membrane 30 using the air blow pressurized air is completed, for example, the backwash drain valve 71 and the air blow pressurized air valve 81 are closed, and the water valve 13 to be treated and the water filling valve 83 are closed. The treated water pump 12 is operated in a state where the water is opened, the air in the primary side region is extracted from the water filling line 82 and the treated water is filled in the primary side region, and then filtration of the treated water can be resumed.

Here, in this membrane filtration system 100, the backwash water tank which stores the filtrate used for backwashing of the filtration membrane 30 is not provided, but the backwash pressurized air line 60 arranged in the vicinity of the container 20 is provided. By supplying pressurized air for backwashing through the filter membrane 30, the filter membrane 30 is backwashed using only the filtered water that is substantially present in the secondary region of the container 20. Incidentally, from the viewpoint of sufficiently back-washing the filtration membrane using only the filtered water present in the secondary side region, the volume of the secondary side region should be secured at least 0.5 L per 1 m ^{2 of} the filtration membrane area. It is preferable to secure 2L or more.
In the present invention, the phrase “backwash the filtration membrane using only the filtrate water substantially present in the secondary region of the container” means that the secondary region is not provided with a backwash water tank. This means that the filtration membrane is backwashed using water present in the water and filtered water in the filtrate line that inevitably flows into the secondary region when supplying pressurized air for backwashing.

  Therefore, in this membrane filtration system 100, the configuration of the membrane filtration system 100 can be simplified by eliminating the need for a backwash water tank. However, as shown in FIGS. When the backwashing is started, air (pressurized gas) flows into the secondary region of the container 20 immediately after the backwashing is started (for example, within 1 second from the backwashing start). And in the part into which the air in a secondary side area | region flowed in, filtered water does not flow into the water flow hole 31 (primary side area | region) sequentially.

  However, in this membrane filtration system 100, since the spacer 40 is disposed above the filtration membrane 30, even if air flows into the secondary region immediately after the start of backwashing, the water level in the secondary region is It drops from the portion around the spacer 40. Therefore, in the membrane filtration system 100, the water level in the secondary region immediately after the start of backwashing is positioned vertically above the upper end position of the filtration membrane 30 for a predetermined time, and the entire filtration membrane 30 is uniformly and It can be backwashed effectively.

  Further, in this membrane filtration system 100, since the spacer 40 has a reduced diameter portion composed of the tapered portion 42 and the small diameter portion 43, compared to the case where the outer diameter of the spacer 40 is constant in the axial direction, The volume of the internal space 21 located on the radially outer side of the spacer 40 can be increased. Accordingly, the amount of filtrate water existing between the outer peripheral surface of the spacer 40 and the inner peripheral surface of the container 20 facing the spacer 40 is increased, and the water level of the filtrate water in the secondary region is the upper end of the filtration membrane 30. The entire time of the filtration membrane 30 can be backwashed more effectively by extending the time that is located vertically above the position.

  Furthermore, in this membrane filtration system 100, the position where the pressurized air for backwash flows into the secondary side region (that is, the connection position between the filtrate water line 50 and the container 20 in the illustrated example) is the upper part of the container 20. And opposed to the spacer 40. Therefore, compared with the case where the position where the backwashing pressurized air flows is at the lower part of the container 20, the filtered water (backwashing water) into the water passage hole 31 by the air flow in the secondary region. The flow of is not disturbed. Moreover, compared with the case where the position where the backwashing pressurized air flows is opposed to the outer peripheral surface of the filtration membrane 30, filtered water into the water passage hole 31 by blowing air to the outer peripheral surface of the filtration membrane 30. (Backwash water) inflow is not disturbed.

When pressurized filtered water is allowed to flow into the water passage hole 31 (primary side region) at a time, the inside of the water passage hole 31 is caused by the distribution of the degree of clogging in the filtration membrane 30. In some cases, clogging substances (clogging substances) may not be peeled uniformly.
Therefore, in the membrane filtration system 100, from the viewpoint of more effectively backwashing the entire filtration membrane, it is preferable to flow the pressurized filtrate water into the water passage hole 31 (primary side region) in a plurality of times. It is further preferable that the first inflow amount is equal to or less than the amount of filtered water existing between the spacer 40 and the inner peripheral surface of the container 20. This is because if the filtered water is divided into a plurality of times and flows into the water passage hole 31, the clogging substances that have not been separated by the first filtered water inflow can be separated by the second and subsequent filtered water inflows. . Further, if the first inflow amount is set to be equal to or less than the amount of filtered water existing between the spacer 40 and the inner peripheral surface of the container 20, the filtration membrane 30 in the secondary side region has a filtration membrane 30 at the first water flow. Is not lowered to the upper end position (the position shown in FIG. 3B). Therefore, the filtered water can be passed twice or more in a state where the pressure is uniformly applied to the outer peripheral surface of the filtration membrane 30, and the entire filtration membrane can be backwashed more effectively.
Incidentally, the pressurized filtered water is divided into a plurality of times, for example, by controlling the opening / closing of the backwash drain valve 71 using a control device, or by controlling the opening / closing of the backwash drain valve 71 by a timer. It is possible to flow into the water passage hole 31.

  As mentioned above, although the membrane filtration system of this invention was demonstrated using an example, the membrane filtration system of this invention is not limited to the said example, A change may be suitably added to the membrane filtration system of this invention. it can.

  Specifically, in the membrane filtration system 100 of the above example, a spacer 40 having a cylindrical shape and a reduced diameter portion (tapered portion 42 and small diameter portion 43) is used as a spacer. However, in the membrane filtration system of the present invention, As shown in FIG. 4, the spacer 40 </ b> A may not have a reduced diameter part, and may be a solid body. When the spacer 40A is solid, the upper end face of the filtration membrane 30 is closed by the spacer 40A, so that the filtrate is dead-end filtered.

  Moreover, in the membrane filtration system 100 of the above example, three columnar filtration membranes 30 are used. However, in the membrane filtration system of the present invention, the number of filtration membranes to be used is not limited to three, but one. There may be more than one. For example, when a plurality of filtration membranes are arranged in a container, the shape of the container and the arrangement position of the filtration membrane in the container can be any shape and position. Specifically, the plurality of filtration membranes may be arranged in a rectangular parallelepiped container so as to be positioned on a straight line in plan view, or in a cylindrical container on a circumferential line in plan view or in plan view. You may arrange | position so that it may be located on a radiation. Furthermore, in the membrane filtration system of the present invention, a chemical addition backwash (CEB) may be performed by providing a line for adding chemicals in the secondary region.

  Furthermore, in the membrane filtration system 100 of the above example, a plurality of columnar filtration membranes 30 are accommodated in one container 20, but in the membrane filtration system of the present invention, as shown in FIG. A plurality of containers 20 may be provided. In addition, when a backwash water tank is installed and the water in the backwash water tank is pressurized using backwashing pressurized air and backwashing is performed, membrane filtration provided with a plurality of containers containing one filtration membrane In the system, not all filtration membranes can be washed uniformly due to pressure loss in the pipes, and the degree of filtration membrane washing may vary between containers. However, in the membrane filtration system 100A according to the present invention, the position where the backwashing pressurized air is introduced (backwashing pressurized air line 60) is close to the container 20 and substantially within the secondary region of each container. Therefore, the filtration membrane in each container 20 can be backwashed uniformly.

  According to the present invention, there is provided a membrane filtration system using a columnar filtration membrane having a water passage hole and a separation layer located on the surface of the water passage hole, and effectively backwashes the filtration membrane with a simple configuration. A possible membrane filtration system can be provided.

10 treated water tank 11 treated water line 12 treated water pump 13 treated water valve 20 container 21 internal space 22, 23 partition plate 24 first common flow path 25, 26 partition plate 27 second common flow path 30 filtration membrane ( Ceramic membrane)
31 Water passage hole 32 Outer peripheral surface 40 Spacer 41 Large diameter portion 42 Taper portion 43 Small diameter portion 44 Annular recess 45 Packing 46 O-ring 47 Packing 50 Filtration water line 51 Filtration water valve 60 Backwashing pressurized air line 61 Backwashing addition Pressurized air valve 70 Backwash drainage line 71 Backwash drainage valve 80 Air blow pressurized air line 81 Air blow pressurized air valve 82 Water filling line 83 Water filling valve 91 Water passage hole 92 Filtration membrane 93 Container 94 Secondary region 100 Membrane filtration system 40A Spacer 100A Membrane filtration system

Claims (3)

A columnar filtration membrane having a water passage hole extending in the axial direction between both end faces and a separation layer positioned around the water passage hole, and a container in which the filtration membrane is housed in an internal space, A membrane filtration system comprising a filtration device that obtains filtered water by filtering the treated water supplied into the water passage holes of the filtration membrane through the separation layer,
The container containing the filtration membrane is installed with the axis of the filtration membrane oriented in a substantially vertical direction,
The internal space of the container is divided into a primary side region through which the treated water flows and a secondary side region through which the filtered water flows,
Backwashing mechanism for backwashing the filtration membrane by pressurizing the filtered water present in the secondary region using a pressurized gas, and allowing the filtered water to flow into the primary region;
A spacer having a smaller diameter than the internal space, disposed between the upper end surface of the filtration membrane and the upper end surface of the internal space,
A membrane filtration system, further comprising:   The backwashing mechanism divides the pressurized filtered water into the primary side region divided into a plurality of times, and at least the first inflow amount to the primary side region, the outer peripheral surface of the spacer, 2. The membrane filtration system according to claim 1, wherein the amount is less than or equal to the amount of filtered water existing between the inner peripheral surface of the container facing the spacer. The membrane filtration system according to claim 1 or 2, wherein the spacer has a reduced diameter portion whose outer diameter is smaller than the spacer end portion on the filtration membrane side.

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