JP5257037B2 - Immersion membrane separation module and flat membrane element replacement method - Google Patents

Description

The present invention relates to immersion type separation membrane module for use in applications membrane bioreactor.

  Instead of the final sedimentation basin in the activated sludge method, a membrane separation activated sludge method has been developed and is becoming popular. This membrane separation activated sludge method is a treatment method that uses a separation membrane such as a precision membrane or an ultrafiltration membrane instead of the final sedimentation basin of a normal activated sludge method, and is a treatment method in a biological reaction tank. There is an advantage that the installation area can be reduced while keeping the biomass of treated water (generally MLSS (= Mixed Liquor Suspended Solids)), and the separation of sludge and treated water. Since it is carried out by membrane filtration regardless of gravity sedimentation, there is an advantage that SS (= Suspended Solids, suspended matter) does not flow out into the treated water, and clear treated water can be obtained.

  When performing membrane separation treatment by the membrane separation activated sludge method, in order to clean the surface of the separation membrane, a diffuser tube is usually installed under the separation membrane to generate bubbles (aeration), and the upward flow of bubbles is reduced. The membrane surface is cleaned by acting on the membrane surface. On the other hand, this aeration is also necessary for supplying oxygen to the activated sludge for biological treatment of the liquid to be treated. That is, in the membrane separation activated sludge method, aeration plays both roles of cleaning the membrane surface and supplying oxygen for biological treatment.

  As an immersion type membrane filtration module, for example, Patent Document 1 discloses an immersion type membrane module that can keep a gap between adjacent filtration membranes constant regardless of an operator's technique by providing a recess in a case. Yes. However, in such a submerged membrane module, in order to reduce the vibration of the membrane element during aeration, it is necessary to reduce the difference between the width of the recess and the membrane element as much as possible. It is difficult to load and unload and balance is very difficult.

In addition, Patent Document 2 includes a filtration plate having a support plate and filtration membranes arranged on both sides of the support plate, and a housing in which a plurality of filtration membrane elements are accommodated in parallel with each other, and the filtration membrane Protrusions are provided at the left and right outer ends of the elements, and the adjacent filtration membrane elements are positioned by contacting the protrusions, and a recess is provided at the tip of at least one of the protrusions. Discloses a filtration membrane module characterized in that a convex portion that can be loosely fitted to the concave portion of the filtration membrane element is provided, and the convex portion of the inner side portion of the housing is fitted to the concave portion of the filtration membrane element. . However, in the case of this configuration, a force in the thickness direction of the filtration membrane element is applied to the plurality of filtration membrane elements in parallel, and the plurality of filtration membrane elements are pressed against each other. When exchanging the filtration element, it is necessary to release this press, so that there is a problem that the exchanging operation itself is very complicated.
JP-A-4-281828 Japanese Patent No. 3979114

Accordingly, the present invention is to facilitate the loading and replacement of the flat membrane element to the case, there is provided an immersion type separation membrane module which can reduce damage of the flat membrane element.

In order to solve this problem, the present invention comprises the following means.
(1) in a box-shaped case, in an immersion type membrane separation module arranged so as to be mutually parallel flat membrane element having sheets double in the vertical direction having a projection, made some or all of the box-shaped case is a resin And the inside of the box-shaped case is divided into a plurality of sections by providing guides in the box-shaped case, and two or more and five or less flat membrane elements are respectively provided in the sections. are arranged, the interval of the guide each other, not less than 2 times the maximum width of the flat membrane element in a direction perpendicular to the guide, or one, projecting Okoshido mechanics of the flat membrane element preparative within the compartment, and immersion type membrane separation module, characterized in that the flat film element in the protrusion and the guide is flat membrane element together by being respectively abut are position regulating.
(2) The submerged membrane separation module according to (1), further comprising a vibration preventing tool.
(3) A part or all of the material of the box-like case is any one of acrylonitrile-butadiene-styrene copolymer synthetic resin, vinyl chloride resin, and polypropylene resin, described in (1) or (2) Submerged membrane separation module.
(4) The submerged membrane separation module according to any one of (1) to (3), wherein a cross-sectional shape in the horizontal direction of the guide with respect to the ground contact surface is any of a rectangle, a semicircle, a triangle, and a trapezoid .
(5) The submerged membrane separation module according to any one of (1) to (4), wherein a partition width of a cross section in a horizontal direction with the ground contact surface of the guide is 2 mm or more and 30 mm or less.

  According to the present invention, it is possible to provide an inexpensive submerged separation membrane module and a method for replacing a flat membrane element that can be easily loaded and replaced in a housing, can effectively fix the flat membrane element, and can reduce damage caused by vibration. It becomes possible.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a submerged membrane separation module in which a plurality of flat membrane elements are arranged in a box-like case so as to be parallel to each other in the vertical direction. The box-shaped case includes a side panel 1 and a guide panel 3 that fix the flat membrane element 4. A guide 2 for separating two to five flat membrane elements 4 is attached to the guide panel 3.

In FIG. 2, the figure which looked at the state which loaded the flat membrane element 4 in the box-shaped case from upper direction is shown. Two flat membrane elements 4 are loaded inside the side panel 1, and guides 2 are provided on the guide panel 3 at intervals of two flat membrane elements 4. In each section divided by the guide 2, the flat membrane elements 4 and the flat membrane element 4 and the guide 2 are in contact with each other, and the positions of the flat membrane elements 4 are regulated. A casing, that is, a box-like case is formed from the side panel 1 and the guide panel 3.

The side panel 1 and the guide panel 3 need to be made of resin from the viewpoint of rigidity and cost, and are usually made of a resin material such as ABS (acrylonitrile-butadiene-styrene copolymer synthetic resin). From the viewpoint of life and life, a box-shaped case may be formed by combining with stainless steel or other members. As the resin material, ABS resin, vinyl chloride resin, polypropylene resin, and the like are preferable from the viewpoint of processability, durability, and economy, but are not limited thereto.

Two to five flat membrane elements are bundled and loaded between guide panels. In order to ensure the flow of air and sludge from below, the flat membrane element is provided with a clearance 6 as shown in FIG. By making 2 to 5 flat membrane elements into one set, it is possible to reduce the number of guides compared to providing guides for each one, leading to cost reduction for the entire submerged separation membrane module. . In addition, if one sheet is loaded, if the loading direction is not correct, the flat membrane element and the guide may get caught, resulting in damage to the flat membrane element. As a result, the chance of the flat membrane element and the guide being caught can be reduced, and element damage can be suppressed.

  As for the upper limit of one set, normally, the maximum number of sheets that can be worked by one worker is 5, and if it exceeds 5, the work becomes difficult. The number of membrane elements is 5 or less. The weight of a normal flat membrane element is about 1 kg to 5 kg per sheet.

  The width of the flat membrane element 4 (d in FIG. 2) should be judged from the strength, economy, and ease of handling of the flat membrane element 4, but is usually 2 mm or more and 30 mm or less.

The gap provided between the membranes of the flat membrane element 4 is an air flow path for sludge and cleaning, and the interval (a _{1 in} FIG. 2) is usually about 5 mm to about 50 mm.

  In FIG. 2, the protrusion 11 is provided on the resin plate constituting the flat membrane element 4, but by contacting the protrusion, a gap between the films can be secured and a sludge and air flow path can be secured. Note that the width of the protrusion (b in Fig. 2) is preferably about 2 to 30 mm to ensure strength and flow path, and the appropriate cross-sectional shape in the horizontal direction with respect to the ground plane is a rectangle or trapezoid. do it.

The horizontal cross-sectional shape of the guide 2 provided in the box-shaped case with respect to the ground contact surface is preferably selected to have a shape that appropriately divides the flat membrane element 4 such as a rectangle, trapezoid, semicircle, or triangle. Further, it is desirable that the partition width (c in FIG. 2) in the horizontal section of the guide 2 with respect to the ground contact surface is 2 mm or more and 30 mm or less. If it is 2 mm or less, there will be a problem with the strength of the guide 2, and if it is 30 mm or more, the width (a ₂ ) of the air flow path will become too large and efficient air cleaning will not be possible.

  In FIG. 3, the external appearance of the flat membrane element 4 is shown. The flat membrane element 4 has a flat membrane 5 attached to both surfaces of a resin board such as ABS. The flat membrane element 4 is provided with a nozzle 7 for taking out permeated water in addition to a flow path for allowing water to permeate. The flat membrane is made of PVDF (polyvinylidene fluoride) or PE (polyethylene), but is not limited.

FIG. 4 shows the submerged membrane module shown in FIG. 1 provided with a vibration preventing tool 8 for fixing each flat membrane element 4 and suppressing vibrations. A flat membrane element 4 is loaded in a box-shaped case formed of the side panel 1 and the guide panel 3, and the flat membrane element 4 is divided into two to five sheets by a guide 2 provided on the guide panel 3. Vibration prevention tools 8 for fixing the flat membrane elements 4 and suppressing vibrations are provided at the three upper portions of the loaded flat membrane elements 4. The vibration preventing tool 8 is made of an elastic material such as EPDM rubber, and preferably has a comb-like shape as shown in FIG. 4 so that each flat membrane element can be effectively suppressed. Here, although the thing attached to the upper part of the flat membrane element 4 is shown, it is also possible to attach a vibration prevention tool to the lower part of the flat membrane element like the upper part of the flat membrane element. The filtered water filtered by the flat membrane element 4 is collected from the tube 9 to the water collecting pipe 10.

In general, the flat membrane element needs to be replaced when it is damaged or deteriorated due to foreign matters mixed into the raw water component or excessive aeration. In addition, when there is no guide for partitioning the flat membrane element during replacement, the flat membrane element is inclined to one side, and it takes time and effort to lift and replace, which is inconvenient for on-site replacement work.

Therefore, FIG. 5 illustrates a method of pulling up and replacing two or more flat membrane elements 4 partitioned by a guide for each partition in the submerged membrane separation module shown in FIG. When a guide provided in the guide panel 3 pulls the flat sheet membrane element 4 functions as an introduction guide, smoothly and it is possible to pull up exchanging flat membrane element 4.

  Next, an embodiment when the present invention is used for actual water treatment will be described. In FIG. 6, raw water 12, which is organic sewage such as municipal sewage, is sent to a membrane separation tank 14 by a raw water pump 13. Activated sludge is stored in the membrane separation tank 14 and is loaded with a submerged membrane separation module 21. Air blown from the blower 15 is aerated through the air diffuser 16 from the lower part of the submerged membrane separation module 21. This aeration is performed for cleaning the membrane surface and supplying air to the activated sludge. The biologically treated water by the activated sludge is solid-liquid separated by the submerged membrane separation module 21 while being sucked by the suction pump 17 and is discharged as treated water 19 or reused. Moreover, the activated sludge propagated by the biological treatment is periodically extracted as excess sludge 20 by the excess sludge pump 18, and the activated sludge concentration in the membrane separation tank 14 is kept constant.

  Here, the raw water 12 is an organic wastewater that is treated with activated sludge, and is not particularly limited, including sewage, factory wastewater, and the like. The raw water pump 13 is a pump for feeding the organic sewage, and a centrifugal pump, a diffuser pump, a spiral mixed flow pump, a mixed flow pump, a piston pump, a plunger pump, a diaphragm pump, a gear pump, a screw pump, a vane pump, A cascade pump, a jet pump, etc. can be used.

  The membrane separation tank 14 is a tank for immersing the submerged membrane separation module 21 in the activated sludge liquid and performing aeration. Although the material is not particularly defined, the membrane separation tank 14 has durability against raw water and chemicals to be used. It is desirable. For example, concrete or plastic such as polyethylene can be used.

  The submerged membrane separation module 21 is a submerged membrane separation module loaded with a flat membrane element according to the present invention. The blower 15 is a device that blows air, and generally a blower, a compressor, or the like is used. The air diffuser 16 is not particularly limited as long as it can generate bubbles in the activated sludge, but an air diffuser having an air discharge hole in a pipe made of vinyl chloride or stainless steel is usually used. . In addition, a porous rubber, ceramic, a diffuser tube using a membrane, and the like can be used. The suction pump 17 is a pump that sucks the membrane permeated permeated water, and is not particularly limited in shape, but a pump that is normally operated at 300 kPa or less from a reduced pressure state is used. Further, instead of providing the suction pump 17, it is also possible to perform membrane filtration using the natural water head difference as a driving force.

  The excess sludge pump 18 is a pump for periodically extracting excess sludge in order to keep the MLSS concentration in the aeration tank constant. There is no particular limitation as long as sludge with high viscosity can be fed. The MLSS concentration in the membrane separation activated sludge method is about 3,000 to 20,000 mg / L, but the MLSS concentration for maintaining a more stable membrane filtration flux is about 5,000 to 15,000 mg / L. Operation conditions such as filtration flux (flux) and hydraulic residence time (HRT) in activated sludge should be optimized under the conditions of wastewater properties and concentration. The filtration flux is about 0.2 m / day to 2.0 m / day, and the hydraulic residence time is about 3 to 24 hours.

Next, replacement of the flat membrane element will be described. For replacement, replacement due to life or replacement due to trouble can be considered. The life varies greatly depending on the use environment and the flat membrane element, but is generally about 1 to 7 years. On the other hand, replacement by trouble is necessary when the submerged membrane separation module is damaged due to foreign matter such as blades or some organic solvents mixed in the raw water, or when mechanical damage due to excessive aeration, etc. It becomes. At the time of replacement, a flat membrane element for replacement is prepared, and the replacement work is performed using a guide with a scaffold placed on the upper part of the membrane separation tank. At the time of this replacement work, the introduction of the guide eliminates the need for lifting the submerged membrane separation module and disassembling and replacing it outside the tank, making the work much easier and shortening the replacement time.

The present invention, in an immersion type separation membrane module for use in membrane bioreactor for processing sewage sewage, etc., can be exchanged for economical and film is utilized in an easy immersion type separation membrane module.

It is a schematic diagram of the immersion type separation membrane module using this invention. It is a partial view from the upper part of the immersion type separation membrane module of this invention. It is a figure which shows the flat membrane element which concerns on this invention. It is a perspective view which shows the immersion type separation membrane module and vibration prevention tool which concern on this invention. It is a perspective view which shows the replacement | exchange method of the flat membrane element in the immersion type separation membrane module of this invention. It is a schematic diagram which shows embodiment at the time of using this invention for an actual water treatment.

Explanation of symbols

1. Side panel Guide 3. Guide panel 4. Flat membrane element 5. Flat membrane 6. Clearance 7. Nozzle 8. 8. Vibration prevention tool Tube 10. Water collecting pipe 11. Protrusion 12. Raw water13. Raw water pump 14. Membrane separation tank 15. Blower 16. Air diffuser 17. Suction pump 18. Excess sludge pump 19. Treated water 20. Surplus sludge 21. Immersion type membrane separation module a ₁ . Intervals between gaps provided between the membranes of the flat membrane element a ₂ . Width of air flow path b. Width of protrusion c. Separation width between the ground contact surface and the horizontal section of the guide d. Flat membrane element width

Claims (5)

In a box-shaped case, in an immersion type membrane separation module arranged so as to be mutually parallel flat membrane element having sheets double in the vertical direction having a protrusion, some or all of the box-shaped case is made of resin, And the inside of the box-shaped case is divided into a plurality of sections by providing a guide in the box-shaped case, and two or more and five or less flat membrane elements are arranged in each section , spacing of the guide each other, not less than 2 times the maximum width of the flat membrane element in a direction perpendicular to the guide, or one, projecting Okoshido mechanics of the flat membrane element preparative within the compartment, and flat film immersion type membrane separation module, characterized in that the element in the protrusion and the guide is flat membrane element together by being respectively abut are position regulating.   The submerged membrane separation module according to claim 1, further comprising a vibration preventing tool.   3. The submerged membrane separation according to claim 1, wherein a part or all of the material of the box-shaped case is one of acrylonitrile-butadiene-styrene copolymer synthetic resin, vinyl chloride resin, and polypropylene resin. module. The submerged membrane separation module according to any one of claims 1 to 3, wherein a cross-sectional shape in the horizontal direction of the guide with respect to the ground plane is any one of a rectangle, a semicircle, a triangle, and a trapezoid. The submerged membrane separation module according to any one of claims 1 to 4, wherein a partition width of a cross section in a horizontal direction with the ground plane in the guide is 2 mm or more and 30 mm or less.

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