JP6077223B2 - Drainage membrane filtration device - Google Patents

Description

  The present invention relates to a drainage membrane filtration apparatus using a filtration membrane, which is used for treatment of wastewater containing suspended substances such as factory wastewater.

  Conventionally, in a wastewater treatment facility for purifying wastewater containing suspended solids such as factory wastewater, a membrane filtration tank using a filtration membrane is installed downstream of the aeration tank to filter sludge generated in the aeration tank. (For example, patent document 1).

  In such a drainage membrane filtration apparatus using a membrane filter module, a diffuser for supplying filtration membrane cleaning air is installed in the membrane filtration tank in order to prevent the wastewater treatment capacity from being reduced due to clogging of the filtration membrane. Then, the surface of the filtration membrane is cleaned by supplying air from below the filtration membrane module.

JP 2003-094086 A

  However, the sludge contained in the drainage easily adheres to the air jet port provided upward in the diffuser disposed below the membrane filtration tank, and clogs the jet port when growing as a sludge mass. As a result, there is a problem that the filtration membrane is blocked from being washed with air, the filtration membrane is clogged, and it is difficult to continuously perform the waste water treatment.

  An object of the present invention is to solve the above-described problems by preventing the discharge port of the diffuser that supplies the cleaning air for the filtration membrane from being clogged so that the waste water treatment can be continued stably. The object is to provide a membrane filtration device.

  In order to achieve the above-described object, a drainage membrane filtration device according to the present invention is a device for filtering suspended substances in wastewater by a filtration membrane, and a filtration tank for storing wastewater to be filtered; A filtration membrane module that is installed in a filtration tank and filters the waste water through a number of porous filtration membranes, and is installed below the filtration membrane module in the filtration tank, and is filtered by the filtration membrane module A diffuser for supplying air for cleaning the filtration surface of the membrane, the diffuser projecting from the diffuser main body to form an air introduction space from the outside, and introduced into the introduction space A cylindrical nozzle that ejects air into the filtration tank.

  According to this configuration, the air for cleaning the filtration membrane is ejected from the diffuser main body, not directly from the diffuser main body, through the nozzle protruding from the diffuser main body, so that sludge adheres to the nozzle outlet. However, sludge can be easily removed by the pressure of the air passing through the narrow passage in the nozzle. Therefore, clogging of the jet port of the diffuser is effectively prevented, and the drainage membrane filtration device can be continuously operated stably.

  In the drainage membrane filtration device according to an embodiment of the present invention, it is preferable that the diffuser is installed in the filtration tank so that a jet outlet for ejecting air from the nozzle faces downward. According to this configuration, since the nozzle outlet is directed downward, the accumulation of sludge at the outlet is suppressed, and clogging of the diffuser outlet is more effectively prevented.

  In the drainage membrane filtration device according to an embodiment of the present invention, the diffuser is disposed between the adjacent filtration membrane modules, and the nozzle protrudes on a plane facing downward of the diffuser body. It is preferable. According to this configuration, when the cleaning air ejected from the nozzle rises in the filtration tank, the plane facing downward of the diffuser body functions as a deflecting plate that deflects the air, and the air is efficiently filtered. Therefore, the filtration membrane can be efficiently washed.

  As described above, according to the drainage membrane filtration device according to the present invention, it is possible to prevent the discharge port of the diffuser that supplies the filtration membrane cleaning air from being clogged and to continue the wastewater treatment stably. .

It is the schematic which shows the structure of the waste water membrane filtration apparatus which concerns on one Embodiment of this invention, (a) is a side view, (b) is a front view. It is a block diagram which shows an example of the waste water treatment facility with which the waste water membrane filtration apparatus of FIG. 1 is applied. It is a perspective view which shows the structure of the filtration tank of the waste water membrane filtration apparatus of FIG. It is a top view which shows the principal part of the filtration tank of FIG. It is a front view which shows the structure inside the drainage membrane filtration apparatus of FIG. It is a side view which shows the structure inside the drainage membrane filtration apparatus of FIG. It is a side view which shows the attachment structure of the diffuser of the waste water membrane filtration apparatus of FIG.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments.

  FIG. 1 is a schematic diagram showing a configuration of a drainage membrane filtration device 1 according to an embodiment of the present invention. The drainage membrane filtration device 1 is a device that is mainly used in a wastewater treatment facility for purifying wastewater W discharged from a factory, and filters suspended substances such as sludge in the wastewater W through a filtration membrane. As shown in FIG. 2, the waste water W treated in the aeration tank 3 arranged on the upstream side of the drain membrane filtration apparatus 1 is filtered, and the treated water F filtered on the downstream side is treated. Eject to 5.

  As shown in FIG. 1, the drainage membrane filtration device 1 includes a filtration tank 11 that stores drainage W to be filtered, and a plurality of filtration membrane modules 13 that are installed in the filtration tank 11 and filter the wastewater W. Yes. An introduction pipe 15 for introducing the waste water W from the aeration tank 3 (FIG. 2) into the filtration tank 11 is connected to the lower side of the rear of the filtration tank 11 (on the right side in FIG. 1A). The introduction pipe 15 is extended in the width direction Y orthogonal to the longitudinal direction of the filtration tank 11 at the bottom in the filtration tank 11, and has an injection port for injecting the introduced waste water W toward the wall surface of the rear bottom. Have.

  Further, on one side surface of the filtration tank 11 (on the front side in the example of FIG. 1A), there are a plurality of outlet pipes 17 for leading the treated water F filtered by the filtration membrane module 13 to the outside of the filtration tank 11. A water collection header 19 that collects the treated water F derived through the outlet pipe 17, and a discharge pipe 21 that discharges the treated water F collected in the water collection header 19 to the treated water tank 5 (FIG. 2). Is provided. A return pipe 23 for returning the untreated waste water W to the aeration tank 3 is connected above the front surface of the filtration tank 11. Further, the drainage membrane filtration device 1 is stopped inside the filtration tank 11 in front of the filtration tank 11 (left side in FIG. 1A), that is, below the side opposite to the side where the introduction pipe 15 is connected. A drainage pipe 24 is connected to discharge the drainage in the filtration tank 11 to the outside when cleaning is performed.

  An opening / closing door 25 is provided on the rear surface of the filtration tank 11, that is, the surface opposite to the surface to which the return pipe 23 is connected. That is, the rear surface of the main body 27 of the filtration tank 11 is formed as an opening 27a, and the opening 27a is covered by the open / close door 25 so as to be opened and closed as shown in FIG. The open / close door 25 is rotatably connected to the filtration tank body 27 via a hinge mechanism 29.

  In order to ensure the sealing between the opening / closing door 25 and the filtration tank main body 27, a seal member 31 made of an elastic material is attached to the peripheral frame portion 27 b of the opening 27 a of the filtration tank main body 27. Further, a plurality of bolt holes 33 are provided in the frame portion 27 b of the filtration tank main body 27, and bolt insertion holes 35 are provided in the portions of the opening / closing door 25 corresponding to the bolt holes 33. With the open / close door 25 closed, as shown in FIG. 4, a bolt 37 is inserted from the outside into the bolt insertion hole 35 of the open / close door 25 and screwed into the bolt hole 33 of the filtration tank main body 27. The opening 27 a can be closed in a state in which 25 is in close contact with the filtration tank main body 27.

  Further, in order to further improve the sealing performance between the opening / closing door 25 and the filtration tank body 27, the hinge mechanism 29 is not only rotatable, but also filters the opening / closing door 25 with the opening / closing door 25 closed. The tank body 27 has a structure that can be adjusted in position parallel to the longitudinal direction X of the filtration tank 11. Specifically, the hinge mechanism 29 is a rotating shaft 39 that is provided at a connecting portion of the rotation tank 39 attached to the connecting portion 25 a of the open / close door 25 and the filtration tank main body 27 and rotatably supports the rotating shaft 39. An insertion hole 41 a through which the rotation shaft 39 of the rotation support member 41 is inserted is formed as a long hole extending in the longitudinal direction X of the filtration tank 11.

  The filtration membrane module 13 shown in FIG. 5 uses a hollow fiber membrane 51 as a filtration membrane. Specifically, the filtration membrane module 13 is configured by linearly arranging hollow fiber membrane bundles 53 formed by binding a large number of hollow fiber membranes 51 in the width direction Y. The filtration membrane module 13 used in the present embodiment has an external pressure cross flow type, that is, a configuration in which the waste water W is passed from the outside to the inside of each hollow fiber membrane 51 to filter the waste water on the outer surface of the hollow fiber membrane 51. Yes.

  The hollow fiber membrane 51 has a closed end 51a and an open end 51b, and the both ends 51a and 51b of the multiple hollow fiber membranes 51 are bound to form a hollow fiber membrane bundle 53. The closed end 51a side of the hollow fiber membrane bundle 53 is connected to and fixed to a cylindrical support fixing tube 55 disposed in the approximate center in the vertical direction Z in the filtration tank 11, and the open end 51b side is in the filtration tank 11 It is connected to and fixed to a cylindrical water collecting fixed pipe 57 disposed below the vertical direction Z. A plurality of hollow fiber membrane bundles 53 are sequentially connected as described above along the axial direction of the fixed tubes 55, 57, that is, the width direction Y of the filtration tank 11, thereby forming the filtration membrane module 13. In the filtration tank 11, a plurality of (30 in the present embodiment) filtration membrane modules 13 are arranged side by side in the longitudinal direction X of the filtration tank 11.

  As a material for forming the hollow fiber membrane 51, a commonly used material such as polyvinylidene fluoride resin, Teflon (registered trademark), polysulfone resin, ceramic, porous glass, metal or the like may be used. it can. Moreover, although the hole diameter of the hollow fiber membrane 51 may be appropriately selected depending on the type of drainage and the type of suspended substance to be removed, it is preferably in the range of, for example, 0.0001 to 0.5 μm.

  A diffuser 61 for supplying air A for cleaning the outer surface of the hollow fiber membrane 51 of the filtration membrane module 13 is provided in the vicinity of the water collection fixing tube 57 of the filtration membrane module 13 below the filtration layer 11. ing. The diffuser 61 includes a rectangular parallelepiped diffuser main body 61 a having the longitudinal direction Y of the filtration tank 11 as a longitudinal direction, and a cylindrical nozzle 61 b that protrudes from the diffuser main body 61 a and ejects air A into the filtration tank 11. Have. A plurality of nozzles 61b are arranged along the longitudinal direction of the diffuser body 61a. Air A fed from an external blower B (FIG. 2) is introduced into an introduction space 62 formed in the diffuser body 61a.

  As shown in FIG. 6, each of the plurality of diffusers 61 is disposed between adjacent filtration membrane modules 13 and 13. Each diffuser 61 is installed in the filtration tank 11 so that the nozzle 63 of the nozzle 61b faces downward. That is, in each diffuser 61, the nozzle 61b protrudes on one side 61aa of the four side surfaces of the diffuser body 61a substantially perpendicularly to the side surface 61aa, and the nozzle 61b of the diffuser body 61a is provided. The diffuser 61 is attached to the filtration tank 11 so that the side surface 61aa which is a plane faces downward in the vertical direction Z.

  In addition, in the state where the diffuser 61 is attached to the filtration tank 11, the ejection port 63 of the nozzle 61 b of the diffuser 61 is connected to the upper surface of the water collection fixing pipe 57 of the adjacent filtration membrane module 13, that is, the filtration of the hollow fiber membrane 51. It is located below the lowermost end (hereinafter simply referred to as “lowermost end”) 51a of the portion exposed in the tank 11. Further, the side surface 61aa is located above the lowermost end 51a of the hollow fiber membrane 51. That is, the lowermost end 51a of the hollow fiber membrane 51 is disposed such that the position in the vertical direction Z is between the jet port 63 which is the lowermost end of the nozzle 61b and the side surface 61aa which is the uppermost end of the nozzle 61b. Has been.

  Furthermore, it is preferable that the diffuser body 61 a is close to the adjacent filtration membrane module 13 in a state where the diffuser 61 is attached to the filtration tank 11. Specifically, when the width direction dimension of the diffuser body 61a (the dimension in the longitudinal direction X of the filtration tank 11) is D, the distance in the longitudinal direction X from the width direction end of the water collection fixing tube 57 of the filtration membrane module 13 Is preferably in the range of 0 or more and D / 2 or less.

  When the jet outlet is directly formed in the diffuser main body 61a, the sludge easily flows into the diffuser main body 61a from the jet outlet, and the sludge dries in the diffuser main body 61a and the sludge mass grows easily. On the other hand, when the nozzle 61b is provided and the jet outlet 63 is formed at the tip of the nozzle 61b as in this embodiment, even if sludge adheres to the tip of the nozzle 61b during the operation of the blower B, When the sludge mass grows to some extent, it is easily peeled off from the nozzle 61b by the pressure of the air flow passing through the thin cylindrical nozzle 61b. Even when the blower B is stopped, the waste water W stays inside the thin cylindrical nozzle 61b and does not easily flow into the diffuser main body 61a. That is, the jet outlet 63 of the diffuser 61 is not provided directly in the diffuser main body 61a, but is provided at the tip of the nozzle 61b protruding from the diffuser main body 61a. The

  Further, in each diffuser 61, the nozzle 61b is provided on one side 61aa of the four side surfaces of the diffuser main body 61a so as to project perpendicularly to the side surface 61aa, and the jet outlet 63 at the tip of the nozzle 61b extends downward in the vertical direction. When the diffuser 61 is attached to the filtration tank 11 so as to face the cleaning air A that has been jetted into the water in the filtration tank 11 from the jet outlet 63, the side surface on which the nozzle 61 b protrudes is raised. It collides with 61aa and is deflected in the longitudinal direction X, that is, in the direction toward the adjacent filtration membrane module 13. That is, the downward side surface 61aa of the diffuser body 61a functions as a deflecting plate for deflecting the cleaning air A, and the air A rises while efficiently contacting the outer surface of each hollow fiber membrane 51 of the filtration membrane module 13. Therefore, the hollow fiber membrane 51 can be efficiently cleaned.

  In the present embodiment, the example in which the diffuser body 61a has a rectangular parallelepiped shape has been described, but the shape of the diffuser body 61a is not limited thereto. At least the portion of the diffuser body 61a where the nozzle 61b protrudes is formed in a flat shape, and if this surface is disposed downward, the effect of deflecting the cleaning air A can be obtained.

  As shown in FIG. 5, a cylindrical introduction port 71 serving as an inlet for air A is provided on one end face of the diffuser body 61a, and a flat engagement protrusion is provided on the other end face of the diffuser body 61a. 73 is provided. An air introduction path 75 for introducing air A from the outside extends in the longitudinal direction X on one side surface in the filtration tank 11, and is cylindrical from the air introduction path 75 toward the inner side in the width direction of the filtration tank 11. A cylindrical air introduction pipe 77 is projected. As shown in FIG. 7, a support socket 81 having an engaging recess 79 for receiving the protrusion 73 of the diffuser body 61a is provided on the other side surface in the filtration tank 11. The support socket 81 is made of an elastic material such as resin.

  The engagement protrusion 73 has an elongated oval cross section. On the other hand, the engagement recess 79 of the support socket 81 includes a base portion 79a that abuts one of the straight portions 73a and 73a in the oval shape of the cross section of the engagement projection 73, and an engagement projection that protrudes from the base portion 79a. 73 has two projecting pieces 79b and 79b corresponding to the arc-shaped portions 73b and 73b at both ends in the elliptical shape of the cross section.

  With the introduction port 71 of the diffuser body 61a of FIG. 5 fitted to the air introduction pipe 77, the protrusion 73 of the diffuser body 61a is engaged with the engagement recess 79 of the support socket 81 shown in FIG. A diffuser 61 is supported in the filtration tank 11. When engaging the protrusion 73 of the diffuser main body 61a with the engagement recess 79 of the support socket 81, as shown in the figure, one arcuate part 73b of the protrusion 73 is connected to one protrusion piece 79b of the engagement recess 79. The other arcuate portion 73b of the protrusion 73 is fitted into the inner surface of the other protruding piece 79b of the engaging recess 79 in a state where the protruding piece 79b is elastically deformed. In this manner, the diffuser 61 can be easily and reliably attached to the filtration tank 11 without using a connecting member such as an additional bolt. Moreover, since the diffuser 61 can be removed from the inside of the filtration tank 11 by a procedure reverse to the above, the replacement work of the diffuser 61 can be easily performed.

  As shown in FIG. 1, the treated water F filtered by each filtration membrane module 13 is led out to a water collection header 19 through a lead-out pipe 17. One outlet pipe 17 is provided for each of the plurality of filtration membrane modules 13. As each outlet tube 17, a transparent or translucent tube is used. Further, each outlet pipe 17 is provided with an on-off valve 85.

  Since one outlet pipe 17 made of a transparent or translucent tube is provided for each filtration membrane module 13, when the hollow fiber membrane 51 is damaged and a leak of the drainage W occurs, the leak can be easily visually checked. Can be found in. In addition, since each outlet pipe 17 is provided with an opening / closing valve 85, when leakage occurs, only the opening / closing valve 85 corresponding to the filtration membrane module 13 is closed, and the remaining filtration membrane module 13 performs the drainage treatment for a certain period. It is possible to continue. In the drainage membrane filtration apparatus 1 according to the present embodiment, a large number (30 sets) of the filtration membrane modules 13 are used. Therefore, even if the processing by one of the filtration membrane modules 13 is stopped, the remaining filtration membrane modules 13 are used. Has little effect on the processing pressure.

  The treated water F led to the water collecting header 19 is discharged to the treated water tank 5 through the discharge pipe 21. The connection pipe portion 21a, which is a connection portion of the discharge pipe 21 with the water collection header 19, is formed as a branch pipe branched into a plurality (two in this embodiment).

  In this way, by dividing the connection pipe portion 21 a of the discharge pipe 21 with the water collection header 19 into a plurality of parts, the distribution of the suction pressure by the suction pump P disposed downstream of the water distribution pipe 19 within the water collection header 19. Is made uniform. When the suction pressure applied to each filtration membrane module 13 is biased and the suction pressure is concentrated on a specific filtration membrane module 13, the filtration membrane module 13 is likely to be clogged. A clogging chain in which high suction pressure is applied and clogging is likely to occur. However, in this embodiment, since the suction pressure concerning each filtration membrane module 13 is equalized, it becomes possible to continuously operate without causing clogging over a long period as a whole. In addition, the value of the space | interval P along the longitudinal direction X of the space | interval S between adjacent branch pipes and the branch pipe located in the extreme end part in the longitudinal direction X and the edge part of the water collection header 19 is the branch pipe. In consideration of conditions such as the number and the pipe diameter, the suction pressure acting in the water collection header 19 may be set as appropriate.

  As described above, according to the drainage membrane filtration device 1 according to the present embodiment, the filtration membrane cleaning air A is filtered not directly from the diffuser main body 61a but through the nozzle 61b provided on the diffuser main body 61a. Since it is ejected into the tank 11, even if sludge adheres to the jet outlet 63 of the nozzle 61b, the sludge can be easily removed by the pressure of the air A that has passed through the narrow passage in the nozzle 61b. Therefore, clogging of the jet outlet 63 of the diffuser 61 is effectively prevented, and the drainage membrane filtration device 1 can be continuously operated stably.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention. Therefore, such a thing is also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Drain membrane filtration apparatus 3 To-be-processed liquid introduction apparatus 5 Mixer 7 Filtration apparatus 9 Gas amount adjustment apparatus 11 Filtration tank 13 Filtration membrane module 51 Hollow fiber membrane (filtration membrane)
61 Diffuser 61a Diffuser body 61b Nozzle 62 Introduction space 63 Spout A Air W Wastewater F Treated water

Claims (1)

An apparatus for filtering suspended substances in waste water through a filter membrane,
A filtration tank for storing wastewater to be filtered;
A filtration membrane module installed in the filtration tank and filtering the wastewater through a number of porous filtration membranes;
A diffuser that is installed in the filtration tank and supplies air for cleaning the filtration surface of the filtration membrane of the filtration membrane module;
With
The diffuser projects from a diffuser body that forms a space for introducing air from the outside and a plane that faces downward in the vertical direction of the diffuser body. And a cylindrical nozzle that
It is installed in the filtration tank so that the jet outlet for jetting air from the nozzle faces downward, and is arranged between the adjacent filtration membrane modules ,
The membrane filter of the membrane filter module is arranged such that the vertical position of the lowermost end is between the nozzle outlet and the plane facing downward in the vertical direction of the diffuser body. .

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