Membrane treatment device

Abstract

A membrane treatment apparatus (1) having a plurality of flat membrane elements (2) immersed in a liquid to be treated, wherein a plurality of flat membrane elements (2) are arranged face to face in a first direction, a support member (8) for holding the flat membrane element (2) is provided at one end of one side of the flat membrane element (2) in a second direction, and an air dissipation unit (10) is provided below the flat membrane element (2), and the lower edge of the flat membrane element (2) is formed to extend upward from one side of the second direction toward the other side, or to extend upward and horizontally.

Description

Technical Field

[0001] The present invention relates to a membrane treatment apparatus having a plurality of flat membrane elements immersed in a liquid to be treated. Background Technology

[0002] Conventionally, a membrane treatment apparatus is known to have multiple flat membrane elements immersed in a liquid to be treated, with an air-dispersing unit located below the flat membrane elements. In this type of membrane treatment apparatus, by supplying air or other gases from the air-dispersing unit located below the flat membrane elements, an upward flow of the liquid to be treated is formed near the flat membrane elements. However, if the liquid to be treated contains easily entangled impurities such as fibers or hair, there is a risk that these impurities may become stuck on the lower edge of the flat membrane elements, preventing a smooth supply of liquid to the filter membrane surface. As a result, the flow of the liquid to be treated on the filter membrane surface stagnates, suspended matter accumulates and adheres firmly to the filter membrane surface, and the filter membrane is prone to clogging. Membrane treatment apparatuses that implement countermeasures against impurities such as fibers and hair getting stuck on the lower edge of the flat membrane elements include, for example, a membrane treatment apparatus in Patent Document 1 that positions the front ends of adjacent flat membrane elements differently, and a membrane treatment apparatus in Patent Document 2 that has a screen residue contact suppression section located at the lower part of the flat membrane elements.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 6-198144

[0006] Patent Document 2: Japanese Patent Application Publication No. 2016-168546 Summary of the Invention

[0007] The problem that the invention will solve

[0008] In the membrane treatment apparatuses disclosed in Patent Documents 1 and 2, although it is possible to prevent impurities such as fibers and hair from getting stuck on the lower edge of the flat membrane element, or even if these impurities do get stuck, they are unlikely to cause damage to the filter membrane, once these impurities are stuck on the lower edge of the flat membrane element, they are difficult to remove. Therefore, if treatment continues, there is a concern that the impurities will soon clog the lower edge of the flat membrane element, preventing the smooth supply of the treated liquid to the filter membrane surface. Furthermore, as a result, the flow of the treated liquid on the filter membrane surface stagnates, suspended matter accumulates on the filter membrane surface and adheres firmly, making the filter membrane prone to clogging.

[0009] The present invention was made in view of the above circumstances, and its object is to provide a membrane processing apparatus in which even if impurities such as fibers and hair are stuck on the lower edge of the flat membrane element, these impurities can be easily detached from the lower edge of the flat membrane element.

[0010] Methods for solving problems

[0011] The membrane treatment apparatus of the present invention, which can solve the above-mentioned problems, has the following features: it has a first direction and a second direction in the horizontal direction, and has a height direction, and has a plurality of flat membrane elements immersed in the liquid to be treated. The flat membrane elements are arranged in a plurality of face-to-face arrangement in the first direction. A support member for holding the flat membrane element is provided at one end of one side of the flat membrane element in the second direction. An air dissipation unit is provided below the flat membrane element. The lower edge of the flat membrane element is formed to extend upward from one side of the second direction toward the other side, or to extend upward and horizontally.

[0012] The membrane treatment apparatus of the present invention is configured such that the lower edge of the flat membrane element extends upward from one side of the second direction toward the other, or extends upward and horizontally. Therefore, even if fibers, hair, or other impurities are caught on the lower edge of the flat membrane element, these impurities will easily move from one side of the second direction to the other while being acted upon by the flow of gas supplied from the gas dissipation unit and the upward flow of the liquid being treated. The impurities that have moved to the other side of the second direction from the lower edge of the flat membrane element can smoothly detach from that side. Therefore, it is difficult for impurities to clog the lower edge of the flat membrane element, preventing the smooth supply of the liquid being treated to the filter membrane surface, resulting in stagnant flow of the liquid being treated on the filter membrane surface and the accumulation and firm attachment of suspended matter on the filter membrane surface.

[0013] Preferably, the flat membrane element has a first filter membrane on one side in the first direction and a second filter membrane on the other side, with a flow path material between the first and second filter membranes. This flow path material maintains the gap between the first and second filter membranes and allows the permeate from both the first and second filter membranes to flow through. In this case, it is preferable that the lower edge of the first filter membrane, the second filter membrane, and the flow path material extends upward from one side in the second direction toward the other, or extends upward and horizontally. This flat membrane element ensures a larger membrane area for the first and second filter membranes, increasing the filtration capacity of the flat membrane element. Alternatively, the flat membrane element may have an auxiliary member at its lower end, with the lower edge of the auxiliary member extending upward from one side in the second direction toward the other, or extending upward and horizontally. Even with this flat membrane element, fibers, hair, and other debris stuck to the lower edge of the flat membrane element can easily move to the other side in the second direction.

[0014] Preferably, the flat membrane element has a liquid-impermeable portion at its periphery and a liquid-permeable portion in the inner region of the periphery. The upper edge of the liquid-permeable portion is formed to extend downward from one side in a second direction to the other, or to extend downward and horizontally. With the upper edge of the liquid-permeable portion formed in this way, even if gas enters the interior of the flat membrane element, the gas is easily extracted from one side in the second direction, and gas is unlikely to accumulate in the upper part of the liquid-permeable portion. Therefore, the wider portion of the filter membrane can effectively facilitate the filtration of the treated liquid.

[0015] Preferably, the plurality of flat membrane elements arranged along the first direction are held by a common support member. This facilitates miniaturization of the membrane processing apparatus. Alternatively, the plurality of flat membrane elements arranged along the first direction may be held by separate support members.

[0016] Preferably, the flat membrane element has a discharge section for removing the permeate that has passed through the filter membrane, and a water collection section is provided in communication with the discharge section. Thus, the permeate that has passed through the filter membrane is collected in the water collection section, allowing the permeate to be collected and removed from the membrane treatment apparatus. The support member can also serve as the water collection section, thereby enabling miniaturization of the membrane treatment apparatus.

[0017] Preferably, the lower edge of at least one of the plurality of flat membrane elements arranged along the first direction is higher than the lower edge of the adjacent flat membrane element. This formation of the lower edge of the flat membrane element increases the freedom of movement of inclusions stuck on the lower edge in the first direction, making it difficult for the inclusions to be strongly constrained by the lower edge of the flat membrane element. Therefore, inclusions stuck on the lower edge of the flat membrane element are easily moved from one side to the other in the second direction by the flow of gas supplied from the gas dispersing unit and the accompanying upward flow of the treated liquid.

[0018] Alternatively, the membrane treatment apparatus may include a separating member that faces the end edge of the flat membrane element on the opposite side in the second direction and extends vertically. With this separating member, the flow of gas supplied from the gas dissipation unit facilitates an upward flow of the treated liquid between the flat membrane element and the separating member. Therefore, after the inclusions that have moved from the lower edge of the flat membrane element to the other side in the second direction detach from the lower edge of the flat membrane element, they can easily move smoothly upwards along the separating member.

[0019] Preferably, the gas dissipation unit is configured such that the amount of gas dissipated on one side of the second direction is greater than the amount of gas dissipated on the other side. As a result, the impurities stuck on the lower edge of the flat diaphragm element can be more easily moved from one side of the second direction to the other side by the flow of gas supplied from the gas dissipation unit.

[0020] Invention Effects

[0021] Even if fibers, hair, or other debris are caught on the lower edge of the flat membrane element, the membrane treatment apparatus of the present invention can easily move from one side to the other in the second direction along the lower edge of the flat membrane element, and the debris can smoothly detach from the other side in the second direction. Therefore, it is difficult for debris to clog the lower edge of the flat membrane element, preventing the smooth supply of the treated liquid to the filter membrane surface, resulting in stagnant flow of the treated liquid on the filter membrane surface and the accumulation and firm adhesion of suspended matter on the filter membrane surface. Attached Figure Description

[0022] Figure 1 An example of the structure of the membrane treatment apparatus of the present invention is shown, and a perspective view of the membrane treatment apparatus is also shown.

[0023] Figure 2 Show Figure 1 An example of an exploded perspective view of a flat membrane element in a membrane treatment apparatus.

[0024] Figure 3 Show Figure 1 Other examples of exploded perspective views of the flat membrane element of the membrane treatment apparatus shown.

[0025] Figure 4 Various examples of planar shapes for flat film elements are shown.

[0026] Figure 5 Other configuration examples of the membrane treatment apparatus of the present invention are shown, and a perspective view of the membrane treatment apparatus is shown.

[0027] Figure 6 Other configuration examples of the membrane treatment apparatus of the present invention are shown, and a perspective view of the membrane treatment apparatus is shown. Detailed Implementation

[0028] The membrane treatment apparatus of the present invention includes multiple flat membrane elements immersed in a liquid to be treated, and an air-dispersing unit is provided below the flat membrane elements. Each flat membrane element has a filter membrane, and permeate is obtained by filtering the liquid to be treated through the filter membrane. The membrane treatment apparatus of the present invention supplies air or other gases from the air-dispersing unit located below the flat membrane elements, creating an upward flow of the liquid to be treated near the flat membrane elements. However, if the liquid to be treated contains easily entangled impurities such as fibers or hair, there is a risk that these impurities may become stuck on the lower edge of the flat membrane elements, preventing a smooth supply of liquid to the filter membrane surface. As a result, the flow of the liquid to be treated on the filter membrane surface stagnates, suspended matter accumulates and adheres firmly to the filter membrane surface, and the filter membrane is prone to clogging. The membrane treatment apparatus of the present invention, even when the liquid to be treated contains easily entangled impurities such as fibers or hair, can easily continue filtering the liquid to be treated through the flat membrane elements. The membrane treatment apparatus of the present invention will now be described in detail.

[0029] The membrane treatment apparatus has multiple flat membrane elements immersed in the liquid to be treated. The flat membrane elements are, for example, arranged in a water tank, with the liquid to be treated stored in the water tank and the flat membrane elements immersed in the liquid to be treated.

[0030] The type of liquid being treated is not particularly limited, but since the liquid is filtered through a flat membrane element, it is preferable that the liquid contains impurities, suspended solids, and other solid components. Examples of liquids to be treated include wastewater, excrement, process wastewater generated during wastewater or excrement treatment, factory wastewater from food factories, pulp mills, chemical plants, etc., livestock excrement, wastewater generated from the treatment of livestock waste such as livestock excrement, kitchen wastewater, and activated sludge used in these treatments.

[0031] The flat membrane element is formed in a flat plate shape, with a filter membrane on its main surface. The flat membrane element has a treated liquid side where the treated liquid is present and a permeate side where the permeate is present, separated by the filter membrane. The treated liquid side is the outer side (surface) of the flat membrane element, and the permeate side is the inner side (interior) of the flat membrane element. As a filter membrane, it can capture impurities and suspended matter contained in the treated liquid to obtain the permeate; examples include microfiltration membranes (MF membranes) and ultrafiltration membranes (UF membranes). The filter membrane may also have a larger mesh size than a microfiltration membrane. The raw materials constituting the filter membrane are not particularly limited; examples include resins, ceramics, and metals. Furthermore, from the viewpoint of easily obtaining thin and lightweight flat membrane elements, resin-based filter membranes are preferred.

[0032] The flat membrane element preferably has a take-out section for removing the permeate that has passed through the filter membrane. The take-out section is located on the permeate side of the flat membrane element, allowing the permeate to be removed from inside the flat membrane element. The take-out section may be located on the end face of the flat membrane element or on the membrane surface. The end face of the flat membrane element refers to the side portion surrounding the membrane surface of the flat membrane element, and may not be formed in a planar shape.

[0033] The permeate removed from inside the flat membrane element via the extraction section is preferably collected in the water collection section. This allows the permeate to be collected and removed from the mulch film treatment device. The water collection section is connected to the extraction section.

[0034] Membrane-based filtration utilizes the pressure difference between the treated liquid side and the permeate side of the membrane. Filtration can be performed by pressurizing the treated liquid side of the membrane, depressurizing the permeate side, or a combination of both. Furthermore, in membrane treatment devices, since the flat membrane element is immersed in the treated liquid, the treated liquid side of the membrane is slightly pressurized by water pressure based on the set water depth of the membrane. From the viewpoint of efficient filtration, it is preferable to perform filtration by depressurizing the permeate side of the membrane using a suction pump or the like. Therefore, it is preferable that a pressure-reducing unit such as a suction pump is installed in the membrane treatment device, connected to the removal section and the water collection section of the flat membrane element.

[0035] The flat membrane element preferably comprises a first filter membrane and a second filter membrane. The first and second filter membranes are arranged face-to-face on the main surface of the flat membrane element, with the portion between them forming the permeate side of the flat membrane element. Preferably, the flat membrane element also includes a flow path material between the first and second filter membranes. The flow path material functions as a spacer maintaining the distance between the first and second filter membranes and forms a space between them for the permeate from both the first and second filter membranes to flow through. As the flow path material, a frame, a plate with grooves formed on its surface, fabric, knitted fabric, nonwoven fabric, mesh, etc., can be used. The internal gaps of fabrics, knitted fabrics, nonwoven fabrics, and meshes can function as flow paths for the permeate. The first and second filter membranes are preferably joined to the flow path material using known joining methods such as adhesives or welding.

[0036] The flat membrane element preferably has a liquid-impermeable portion at the periphery of the membrane surface and a liquid-permeable portion in the inner region of the periphery. The liquid-impermeable portion can be formed, for example, by sealing the first and second filter membranes to each other at their respective periphery, or by sealing the first and second filter membranes to the flow path material at their respective periphery. The junction between the first and second filter membranes, or the junction between the first or second filter membrane and the flow path material, is formed such that the liquid to be treated will not permeate through the filter membrane. On the other hand, the liquid-permeable portion is defined as the portion where the liquid to be treated can permeate through the filter membrane. The periphery of the membrane surface can, for example, be defined as the area within 50 mm of the periphery of the filter membrane (preferably within 30 mm, more preferably within 20 mm).

[0037] The thickness of the flat membrane element is not particularly limited, but from the viewpoint of miniaturizing the membrane processing device, it is preferable to be 15 mm or less, more preferably 10 mm or less, and even more preferably 7 mm or less. The size of the flat membrane element in the membrane surface direction (length in the horizontal direction and height direction) can be appropriately set, for example, between 30 cm × 30 cm and 200 cm × 200 cm.

[0038] The membrane treatment apparatus has a first direction and a second direction in the horizontal direction, and a height direction. Multiple flat membrane elements are arranged face-to-face in the first direction. The first and second directions are preferably defined as oriented towards the horizontal direction and substantially orthogonal to each other. The flat membrane elements are preferably arranged such that the membrane surface is substantially perpendicular to the horizontal direction; therefore, the flat membrane elements are preferably arranged such that the membrane surface extends substantially along the second and height directions.

[0039] The number of flat membrane elements arranged along the first direction is not particularly limited as long as there are two or more, but it is preferred to have three or more, and more preferably five or more. The upper limit of the number of flat membrane elements arranged along the first direction can be appropriately set according to the size of the water tank where the membrane treatment device is installed, the amount of liquid being treated, and the water quality. For example, it can be 50 or less, or 30 or less, or 20 or less.

[0040] The membrane surface spacing of the flat membrane elements arranged adjacent to each other along the first direction is preferably 1 mm or more, more preferably 3 mm or more, and even more preferably 5 mm or more. This makes it difficult for inclusions to become trapped between adjacent flat membrane elements, thus ensuring the flow of the treated liquid on the surface of the filter membrane. On the other hand, regarding the upper limit of the membrane surface spacing of the flat membrane elements arranged adjacent to each other along the first direction, from the viewpoint of miniaturizing the membrane treatment device, it is preferably 80 mm or less, more preferably 60 mm or less, and even more preferably 40 mm or less.

[0041] A support member for holding the flat film element is provided at one end of the flat film element in the second direction. The support member secures one end of the flat film element in the second direction to a predetermined position in the membrane processing apparatus. The support member is only provided at one end of the flat film element in the second direction, and not at the other end. Therefore, the flat film element is cantilevered by the support member. The other end of the flat film element in the second direction is in an unconstrained state, allowing for some degree of free movement.

[0042] The support member can be configured to hold the entire height direction of one end of the flat film element in the second direction, or it can be configured to hold only a portion of the height direction. Furthermore, from the viewpoint of stably holding the flat film element, the support member is preferably configured to hold at least a portion of the upper 1 / 3 and at least a portion of the lower 1 / 3 of the area of ​​the end of the flat film element in the second direction.

[0043] The support member can be formed, for example, with a groove extending along the height direction. By embedding the end of the flat film element on one side in the second direction into the groove formed in the support member, the flat film element can be held in the support member. The support member can also be provided as a rod-shaped member through which a plurality of flat film elements arranged in a first direction pass. Only one support member can be provided on one side of the flat film element in the second direction, or two or more can be arranged along the height direction.

[0044] Multiple flat membrane elements arranged along a first direction can be held by a common support member or by separate support members. In the former case, the support member has a certain length in the first direction, and multiple flat membrane elements are held by a single support member. The membrane processing apparatus can process one support member and the multiple flat membrane elements held therein as a unit, which improves the processing capacity of the membrane processing apparatus. In addition, it is easy to miniaturize the membrane processing apparatus. In the latter case, one flat membrane element is held by one support member, and the membrane processing apparatus can process one support member and the flat membrane element held therein as a unit.

[0045] Flat film elements can also be arranged along the second direction with their film surfaces facing each other. In this case, multiple flat film elements are arranged with their film surfaces facing each other along the first direction, and multiple others are arranged along the second direction with their film surfaces facing each other. Preferably, the flat film elements arranged along the second direction are configured such that their respective film surfaces exist on substantially the same plane. The flat film elements thus arranged along the second direction can also be held by a common support member. In this case, a support member is provided between the flat film elements arranged along the second direction, and the flat film elements arranged along the second direction are held by this support member.

[0046] The support member can also function as a water collection unit. In this case, the support member has a hollow space inside, which can function as a water collection unit. The flat membrane element can collect the permeate from inside the flat membrane element into the water collection unit by connecting the permeate outlet to the water collection unit.

[0047] An aeration unit is installed below the flat membrane element. This aeration unit allows air or other gases to be supplied to the treated liquid from below the membrane element. When the treated liquid is activated sludge, the aeration unit supplies oxygen to the activated sludge, thereby promoting the biodegradation of organic matter in the treated liquid. The aeration unit can be any aeration device commonly used in water treatment. Examples of aeration devices include membrane-type aeration devices, diffuser-type aeration devices, and porous aeration devices. Alternatively, a mechanical agitator in water can be used to agitate air or other gases while supplying them to the treated liquid using stirring blades.

[0048] If gas is supplied from below the flat membrane element using a gas dispersing unit, an upward flow of the treated liquid will form near the flat membrane element. However, if the treated liquid contains easily entangled impurities such as fibers or hair, there is a risk that these impurities may become stuck on the lower edge of the flat membrane element, preventing a smooth supply of treated liquid to the filter membrane surface. As a result, the flow of treated liquid on the filter membrane surface stagnates, suspended matter accumulates on the filter membrane surface and adheres firmly, easily leading to clogging of the filter membrane.

[0049] Therefore, in the membrane treatment apparatus of the present invention, the lower edge of the flat membrane element extends upward from one side of the second direction toward the other, or extends upward and horizontally. That is, the lower edge of the flat membrane element is formed such that it is located upward away from the side of the second direction where the support member is provided. In addition, a portion of the lower edge of the flat membrane element may also be a horizontal portion. By forming the flat membrane element in this way, even if fibers, hair, or other impurities are caught on the lower edge of the flat membrane element, the impurities will easily move from one side of the second direction to the other side of the lower edge of the flat membrane element under the action of the flow of gas supplied from the gas dispersing unit and the upward flow of the liquid being treated thereon. Since the end of the flat membrane element on the other side of the second direction is not held by the support member, the impurities that have moved to the other side of the second direction are not obstructed by the support member and can be smoothly detached from the lower edge of the flat membrane element. Therefore, it is difficult to cause inclusions to clog the lower edge of the flat membrane element, thus preventing the smooth supply of the treated liquid to the filter membrane surface. As a result, the flow of the treated liquid on the filter membrane surface stagnates, and suspended matter accumulates on the filter membrane surface and adheres firmly.

[0050] Furthermore, in the membrane treatment apparatus of the present invention, since the end of the flat membrane element on the other side of the second direction is not held by a support member, the end of the flat membrane element on the other side of the second direction can move freely to a certain extent. Therefore, even if inclusions enter between adjacent flat membrane elements, the inclusions can easily detach from between the adjacent flat membrane elements due to the change in the inter-membrane distance between the adjacent flat membrane elements. In particular, the gas supplied from the gas dissipation unit is introduced between the adjacent flat membrane elements, causing the flat membrane elements to swing, and the inter-membrane distance between the adjacent flat membrane elements can easily change.

[0051] The membrane treatment apparatus of the present invention, because the flat membrane element has a cantilever structure in which one end in the second direction is held by a support member and the other end is not held by a support member, also achieves the effect that the deformation state of the flat membrane element in the first direction is not fixed. For example, in the case where the flat membrane element has a double-support structure in which both ends in the second direction are held by support members, if the flat membrane element swells and deforms, the flat membrane element can only deform in the first direction, and this deformation state is fixed. As a result, the inter-membrane distance between adjacent flat membrane elements narrows, and inclusions easily clog between the flat membrane elements. However, because the membrane treatment apparatus of the present invention has a cantilever structure for the flat membrane element, even if the flat membrane element swells and deforms, the flat membrane element can deform in the second direction. Furthermore, even if the flat membrane element deforms in the first direction, its deformation state is not fixed, and the local narrowing of the inter-membrane distance between adjacent flat membrane elements is not fixed. Therefore, the inter-membrane distance between adjacent flat membrane elements can be set narrower in advance, and the membrane treatment apparatus can be miniaturized.

[0052] The lower edge of the flat film element may also be formed with an inclined portion extending upward from one side in the second direction to the other side, and the lower edge may also have a horizontal portion extending in the horizontal direction. The inclined portion of the lower edge of the flat film element may be inclined in a straight line or in a curved shape. Preferably, the inclined portion of the lower edge of the flat film element is formed in a range of 50% or more of the length of the flat film element in the second direction, more preferably 60% or more, and even more preferably 70% or more. The flat film element may also have its entire lower edge formed by the inclined portion.

[0053] The lower edge of the flat membrane element is preferably formed in a shape that extends upward from one side in the second direction to the other side. Specifically, when the length of the lower edge of the flat membrane element in the second direction is defined as L1, and the length in the height direction from the lower end to the upper end of the lower edge of the flat membrane element is defined as L2, the ratio of L2 / L1 is preferably 0.1 or more, more preferably 0.3 or more, even more preferably 0.5 or more, and preferably 1.2 or less, more preferably 1.0 or less, and even more preferably 0.8 or less. By forming the lower edge of the flat membrane element in this way, impurities stuck to the lower edge of the flat membrane element can easily move along the lower edge of the flat membrane element from one side in the second direction to the opposite side, and the membrane area of ​​the filter membrane can be easily and maximally ensured.

[0054] From the viewpoint of maximizing the membrane area of ​​the filter membrane, the flat membrane element preferably has the first and second filter membranes extending to the vicinity of the lower edge of the flat membrane element. In this case, the flat membrane element is formed such that the lower edge of the first filter membrane, the second filter membrane, and the flow path material extends upward from one side of the second direction toward the other, or extends upward and horizontally. The first and second filter membranes preferably extend from the lower edge of the flat membrane element to a range of 50 mm or less, more preferably 30 mm or less, and even more preferably 20 mm or less. The first and second filter membranes may also extend to the lower edge of the flat membrane element. The flat membrane element is also preferably formed such that the lower edge of the liquid permeate portion extends upward from one side of the second direction toward the other, or extends upward and horizontally.

[0055] The flat membrane element can also be configured to have an auxiliary member at its lower end, the lower edge of which extends upward from one side in a second direction toward the other, or extends upward and horizontally. In this case, the auxiliary member is provided below the first filter membrane, the second filter membrane, and the flow path material. For example, conventional flat membrane elements are rectangular in shape with a horizontally extending lower edge. However, by installing an auxiliary member on the conventional flat membrane element whose lower edge extends upward from one side in a second direction toward the other, or extends upward and horizontally, it is possible to form a structure in which fibers, hair, and other impurities are less likely to get stuck on the lower edge of the flat membrane element.

[0056] The shape of the upper edge of the flat membrane element is not particularly limited. However, it is preferable that the upper edge of the liquid permeation portion of the flat membrane element extends horizontally or downwards from one side in the second direction towards the other. With the upper edge of the liquid permeation portion formed in this way, even if gas enters the interior of the flat membrane element, it is difficult for gas to accumulate in the upper part of the other side in the second direction, and the wider portion of the filter membrane can effectively contribute to the filtration of the treated liquid. More preferably, the upper edge of the liquid permeation portion of the flat membrane element extends downwards from one side in the second direction towards the other, or extends downwards and horizontally. Therefore, gas entering the interior of the flat membrane element is easily extracted from one side in the second direction, making it difficult for gas to accumulate in the upper part of the liquid permeation portion.

[0057] The plurality of flat membrane elements arranged along the first direction may have their lower edges aligned at the same height, or some or all of them may have different heights. Furthermore, it is preferable that at least one of the flat membrane elements arranged along the first direction has a lower edge height higher than the adjacent flat membrane element, making it difficult for inclusions to become trapped on the lower edge of the flat membrane element. In this case, because the lower edges of the plurality of flat membrane elements arranged along the first direction are not uniformly heighted, the inclusions trapped on the lower edge of the flat membrane element have increased freedom of movement in the first direction, making it difficult for the inclusions to be strongly constrained by the lower edge of the flat membrane element. Therefore, the inclusions trapped on the lower edge of the flat membrane element are easily moved from one side to the other in the second direction by the flow of gas supplied from the gas dispersing unit and the accompanying upward flow of the treated liquid.

[0058] The lower edge of the plurality of flat film elements arranged along the first direction can be formed in a manner where the height increases every other element, every two elements, or every three elements. Furthermore, it can be formed in a manner where the height increases in two consecutive elements or three consecutive elements; these are not particularly limited. The height of the lower edge of the plurality of flat film elements arranged along the first direction can be two, three, or more than three different types.

[0059] The lower edge of a plurality of flat film elements arranged along a first direction is preferably formed such that, for example, the lower edge of at least one of the flat film elements arranged along the first direction, excluding the flat film element located on the farthest side in the first direction and the flat film element located on the farthest side, is higher than that of the adjacent flat film element. When the flat film elements are formed in this way, a wider gap is formed at the portion where the lower edge of the flat film element is higher, making it more difficult for inclusions to get stuck on the lower edge of the flat film element.

[0060] Preferably, the lower edge heights of adjacent flat film elements arranged along the first direction are different. When the flat film elements are formed in this way, the gap between the films can be formed more widely throughout the lower side of the multiple flat film elements arranged along the first direction, making it more difficult for inclusions to get stuck on the lower edge of the flat film elements.

[0061] The air-diffusing unit located below the flat membrane element is preferably configured such that the air-diffusing volume on one side of the second direction is greater than that on the other side. This allows any debris caught on the lower edge of the flat membrane element to easily move from one side of the second direction to the other due to the flow of gas supplied from the air-diffusing unit. Examples of ways to configure the air-diffusing unit so that the air-diffusing volume on one side of the second direction is greater include: providing more air-diffusing devices on one side of the second direction below the flat membrane element than on the other side; providing more or denser air-diffusing ports on one side of the second direction than on the other side of the air-diffusing device located below the flat membrane element; and providing a greater gas supply to the air-diffusing device located on the other side of the second direction within the air-diffusing device located below the flat membrane element than to the air-diffusing device located on the other side.

[0062] The membrane treatment apparatus may also have a dividing member extending vertically opposite the end edge of the flat membrane element in the second direction. In this case, the dividing member is located on the extension line of the flat membrane element in the second direction. With the dividing member arranged in this way, the flow of gas supplied from the gas dissipation unit facilitates an upward flow of the treated liquid between the flat membrane element and the dividing member. Therefore, after the impurities that have moved from the lower edge of the flat membrane element to the other side in the second direction detach from the lower edge of the flat membrane element, they can easily move smoothly upward along the dividing member. Preferably, the dividing member is located within 100 cm from the end edge of the flat membrane element in the second direction, more preferably within 80 cm, and even more preferably within 50 cm. On the other hand, from the viewpoint that the impurities can move smoothly upward between the flat membrane element and the dividing member, the dividing member is preferably located at least 5 cm away from the end edge of the flat membrane element in the second direction, more preferably at least 10 cm away.

[0063] Preferably, at least a portion of the upper edge of the separating member is below the surface of the liquid being treated, and preferably at least a portion of the lower edge of the separating member is above the bottom surface of the tank. Furthermore, it is preferable that the liquid being treated is present on the other side of the separating member in the second direction. By arranging the separating member in this way, an upward flow is formed on one side of the separating member in the second direction, and a downward flow is formed on the other side, enabling a circulating flow to be formed across the separating member.

[0064] Next, examples of the configuration of the membrane treatment apparatus of the present invention will be described with reference to the accompanying drawings. Furthermore, the membrane treatment apparatus of the present invention is not limited to the embodiments shown in the drawings.

[0065] Figure 1 as well as Figure 2 An example of the configuration of the membrane treatment apparatus of the present invention is shown in the figure. Figure 1 A perspective view of the membrane treatment apparatus is shown. Figure 2 Show Figure 1An example of an exploded perspective view of a flat membrane element in a membrane treatment apparatus is shown. Additionally, in the figures, arrow x indicates a first horizontal direction, arrow y indicates a second horizontal direction, and arrow z indicates the vertical direction.

[0066] The membrane treatment apparatus 1 (1A) has a plurality of flat membrane elements 2. The flat membrane elements 2 are immersed in the liquid to be treated and arranged face-to-face in a first direction x. A support member 8 is provided at one end of the flat membrane element 2 in a second direction y, and the other end of the flat membrane element 2 in the second direction y exists as a free end. Figure 1 In the membrane processing apparatus 1A shown, a plurality of flat membrane elements 2 arranged along a first direction x are held by a support member 8. The support member 8 has a plurality of grooves extending along the height direction z, in which flat membrane elements 2 are inserted and held.

[0067] like Figure 2 As shown, the flat membrane element 2 is constructed by distributing a flow path material 4 between the first filter membrane 3A and the second filter membrane 3B. The flow path material 4 functions as a spacer maintaining the distance between the first filter membrane 3A and the second filter membrane 3B, and also functions as a flow path for the permeate that has passed through the first filter membrane 3A and the second filter membrane 3B. Figure 2 In this design, the first filter membrane 3A and the second filter membrane 3B are formed to be one ring larger than the flow path material 4, and the first filter membrane 3A and the second filter membrane 3B are joined together at the peripheral junction 5. The junction 5 of the first filter membrane 3A and the second filter membrane 3B becomes a liquid-impermeable portion, while the inner region of the peripheral portion becomes a liquid-permeable portion. In addition, a portion of the peripheral portion of the first filter membrane 3A and the second filter membrane 3B becomes a take-out portion 6, where the first filter membrane 3A and the second filter membrane 3B are not joined together, and the permeate that has passed through the first filter membrane 3A and the second filter membrane 3B is taken out.

[0068] exist Figure 1 In this structure, a hollow portion is formed inside the support member 8, which functions as a water collection section 9. The extraction section 6 of the flat membrane element 2 is installed on the support member 8 in a manner connected to the water collection section 9 inside the support member 8. The permeate from the filter membrane 3 of each flat membrane element 2 is collected in the water collection section 9 through the extraction section 6. The water collection section 9 is depressurized by a pressure reducing pump, thereby promoting the permeation of the treated liquid through the filter membrane 3, and the permeate that has passed through the filter membrane 3 is collected in the water collection section 9 through the extraction section 6.

[0069] An air dissipation unit 10 is provided below the flat film element 2. Air or other gases are supplied to the liquid being treated from the air dissipation port 11 of the air dissipation unit 10. By supplying gas to the liquid being treated from the air dissipation unit 10, an upward flow of the liquid being treated is formed near the flat film element 2.

[0070] The lower edge of the flat membrane element 2 is formed to extend upward and horizontally from one side of the second direction y to the other side. This flat membrane element 2 is formed such that even if fibers, hair, or other impurities are trapped on the lower edge of the flat membrane element 2, these impurities will easily move from one side of the second direction y to the other side under the influence of the flow of gas supplied from the aeration unit 10 and the accompanying upward flow of the treated liquid. Impurities that have moved to the other side of the second direction y from the lower edge of the flat membrane element 2 can then be smoothly detached from that side. Alternatively, although not shown in the figures, the entire lower edge of the flat membrane element 2 may extend upward from one side of the second direction y.

[0071] like Figure 2 As shown, the flat membrane element 2 is preferably formed such that the lower edges of the first filter membrane 3A, the second filter membrane 3B, and the flow path material 4 extend upward from one side of the second direction y towards the other side, or extend upward and horizontally. Forming the flat membrane element 2 in this way ensures a larger membrane area for the first filter membrane 3A and the second filter membrane 3B, thereby increasing the filtration capacity of the flat membrane element 2.

[0072] Figure 3 It shows Figure 1 The exploded perspective view of the flat membrane element of the membrane treatment apparatus shown is another example, but the flat membrane element 2 can also be formed with an auxiliary member 7 at its lower end, the lower edge of the auxiliary member 7 extending upward and horizontally from one side of the second direction y towards the other side. Alternatively, although not shown in the figures, the lower edge of the auxiliary member 7 can also be formed so that its entire lower edge extends upward from one side of the second direction y towards the other side. Even with the flat membrane element 2 formed in this way, impurities such as fibers and hair stuck on the lower edge of the flat membrane element 2 can easily move towards the other side of the second direction y from the lower edge of the flat membrane element 2.

[0073] exist Figure 4 Various examples of planar shapes for flat film elements are shown. Figure 4 In the attached diagram, the left side corresponds to one side of the second direction y, and the right side corresponds to the other side of the second direction y. Additionally, the liquid permeation portion of the membrane surface of the flat membrane element is shown enclosed by a single-dotted line.

[0074] Figure 4 (a) shows Figure 1 The planar view of the flat membrane element 2 provided in the membrane treatment apparatus 1A shows that the lower edge of the flat membrane element 2 is composed of an inclined portion and a horizontal portion. Figure 4 The lower edge of the flat film element 2 in (a) is formed to extend upward and horizontally from one side of the second direction y toward the other side. Figure 4The flat film element 2 of (b) is formed such that its lower edge consists only of an inclined portion, and extends upward from one side in the second direction y toward the other side. Figure 4 (a) and Figure 4 In (b), the inclined portions of the lower edge of the flat film element 2 are all formed in a straight line. On the other hand, as... Figure 4 As shown in (c), the inclined portion of the lower edge of the flat film element 2 can also be formed in a curved shape. In either case, even if fibers, hair, or other impurities are stuck on the lower edge of the flat film element 2, these impurities can easily move to the other side of the second direction y from the lower edge of the flat film element 2.

[0075] like Figure 4 As shown in (d), the flat membrane element 2 is preferably formed such that the upper edge of the liquid permeation portion (the portion enclosed by the dashed line) extends downward from one side of the second direction y towards the other side. With the upper edge of the liquid permeation portion formed in this way, even if gas enters the interior of the flat membrane element 2, the gas is easily extracted from the side of the flat membrane element 2 in the second direction y, and gas is unlikely to accumulate in the upper part of the liquid permeation portion. Therefore, the wider portion of the filter membrane 3 can effectively contribute to the filtration of the treated liquid. Furthermore, the same effect can be obtained even if the upper edge of the liquid permeation portion is formed to extend downward from one side of the second direction y towards the other side and in a horizontal direction.

[0076] exist Figure 1 In the gas dispersing unit 10, more gas dispersing ports 11 are provided on one side than on the other side in the second direction y. As a result, more gas can be supplied from the gas dispersing unit 10 to one side compared to the other side in the second direction y. When gas is supplied from the gas dispersing unit 10 in this way, the impurities stuck on the lower edge of the flat diaphragm element 2 are more easily moved from one side of the second direction y to the other side by the flow of gas supplied from the gas dispersing unit 10.

[0077] Figure 5 as well as Figure 6 Other configuration examples of the membrane treatment apparatus of the present invention are shown. Additionally, in Figure 5 as well as Figure 6 In the description of the membrane treatment apparatus, the descriptions that are repeated above are omitted.

[0078] Figure 5 The membrane treatment device 1 (1B) shown is Figure 1Compared to the membrane treatment apparatus 1A shown, the configurations related to the support member 8, the extraction section 6, and the water collection section 9 differ. In the membrane treatment apparatus 1B, a support member 8 is provided through a plurality of flat membrane elements 2 arranged along the first direction x, thereby holding the flat membrane elements 2 in place. Two support members 8 are provided, one at the top and one at the bottom, penetrating the end of the flat membrane element 2 along the second direction y. The support members 8 can also be arranged in this manner. Furthermore, in the portion of the flat membrane element 2 through which the support member 8 passes, the permeate will not leak outside the flat membrane element 2.

[0079] exist Figure 5 In the membrane treatment apparatus 1B shown, the water collection section 9 is separately provided from the support member 8. On each flat membrane element 2, a take-out section 6 is provided on one end face in the second direction y, and the take-out section 6 is provided in communication with the water collection section 9. The permeate from the flat membrane element 2 is collected in the water collection section 9 through the take-out section 6.

[0080] Figure 6 The membrane treatment device 1 (1C) shown in the figure passes through Figure 1 The membrane treatment apparatus 1A shown is provided with a separating member 12. The separating member 12 is positioned opposite the end edge of the flat membrane element 2 in the second direction y and extends in the vertical direction. This arrangement of the separating member 12 strengthens the upward flow of the treated liquid, accompanying the flow of gas supplied from the gas dispersing unit 10, between the flat membrane element 2 and the separating member 12. Therefore, after the inclusions on the lower edge of the flat membrane element 2 move to the other side in the second direction y, they easily detach from the lower edge of the flat membrane element 2 and move smoothly upward along the separating member 12, making it difficult for inclusions to become stuck on the flat membrane element 2 again.

[0081] Industrial availability

[0082] The membrane treatment apparatus of the present invention can be used for the treatment of domestic wastewater or excrement, process wastewater generated during wastewater or excrement treatment, factory wastewater generated by food factories, pulp mills, chemical plants, etc., livestock manure, and wastewater generated from the treatment of livestock waste such as livestock manure. Alternatively, it can be used, as in the membrane separation activated sludge process (MBR), to extract treated water from the activated sludge.

[0083] This application claims the benefit of priority based on Japanese Patent Application No. 2020-173503, filed on October 14, 2020. The entire description of Japanese Patent Application No. 2020-173503, filed on October 14, 2020, is incorporated herein by reference for the purposes of this application.

[0084] Explanation of reference numerals in the attached figures

[0085] 1, 1A, 1B, 1C: Membrane treatment equipment

[0086] 2: Flat membrane element

[0087] 3: Filter membrane, 3A: First filter membrane, 3B: Second filter membrane

[0088] 4: Flow path material

[0089] 5: Joint

[0090] 6: Removal section

[0091] 7: Auxiliary components

[0092] 8: Support components

[0093] 9: Water collection department

[0094] 10: Air Dissipation Unit

[0095] 11: Ventilation outlet

[0096] 12: Separating components

Claims

1. A membrane treatment apparatus having a first direction and a second direction in a horizontal direction, and having a height direction, and having a plurality of flat membrane elements immersed in a liquid to be treated, characterized in that, The flat membrane elements are arranged in a plurality of face-to-face configurations in a first direction. A support member for holding the flat film element is provided at one end of the flat film element in the second direction, and the support member is not provided at the other end of the flat film element in the second direction. An air dissipation unit is provided below the flat membrane element. The lower edge of the flat film element is formed to extend upward from one side of the second direction toward the other side, or to extend upward and horizontally.

2. The membrane treatment apparatus according to claim 1, characterized in that, The flat membrane element has a first filter membrane on one side in a first direction and a second filter membrane on the other side. A flow path material is provided between the first filter membrane and the second filter membrane. The flow path material maintains the gap between the first filter membrane and the second filter membrane and allows the permeate of the first filter membrane and the permeate of the second filter membrane to flow through.

3. The membrane treatment apparatus according to claim 2, characterized in that, The flat membrane element is formed such that the lower edge of the first filter membrane, the second filter membrane, and the flow path material extends upward from one side of the second direction toward the other side, or extends upward and horizontally.

4. The membrane treatment apparatus according to claim 2, characterized in that, The flat film element is formed with an auxiliary member at its lower end, the lower edge of which extends upward from one side in a second direction toward the other side, or extends upward and horizontally.

5. The membrane treatment apparatus according to any one of claims 1 to 4, characterized in that, The flat membrane element has a liquid-impermeable portion at the periphery of the membrane surface and a liquid-permeable portion in the inner region of the periphery. The upper edge of the liquid permeable portion is formed to extend downward from one side of the second direction toward the other side, or to extend downward and horizontally.

6. The membrane treatment apparatus according to any one of claims 1 to 4, characterized in that, Multiple flat membrane elements arranged along a first direction are held by a common support member.

7. The membrane treatment apparatus according to any one of claims 1 to 4, characterized in that, Multiple flat membrane elements arranged along the first direction are each held by different support components.

8. The membrane treatment apparatus according to any one of claims 1 to 4, characterized in that, The flat membrane element has a removal section for removing the permeate that has passed through the filter membrane. A water collection section is provided in communication with the extraction section.

9. The membrane treatment apparatus according to claim 8, characterized in that, The supporting component also serves as the water collection section.

10. The membrane treatment apparatus according to any one of claims 1 to 4, characterized in that, At least one of the plurality of flat film elements arranged along a first direction has a lower edge height that is higher than the lower edge height of the adjacent flat film element.

11. The membrane treatment apparatus according to any one of claims 1 to 4, characterized in that, A separating member is provided, which is opposite to the end edge of the flat film element on the other side of the second direction and extends in the vertical direction.

12. The membrane treatment apparatus according to any one of claims 1 to 4, characterized in that, The air dissipation unit is configured such that the amount of air dissipated on one side of the second direction is greater than the amount of air dissipated on the other side.

Images