JP2015174059A - Filter apparatus and external pressure type filtration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter apparatus and an external pressure type filtration method which are excellent in treatment cost.SOLUTION: A filter apparatus of the present invention includes a filter tank and one or more filtration membrane modules immersed in the filter tank, is an external pressure type filter apparatus purifying a liquid to be treated supplied into the filter tank, and further includes an air bubble feeder supplying air bubbles to the filtration membrane module from below. The inside of the filter tank is pressurized by the air bubbles supplied from the air bubble feeder. Other means for pressurizing the inside of the filter tank may not be provided. The filter tank is an erected air-tightly closable cylindrical body, and the filtration membrane module is preferably arranged in the axial direction of the filter tank. The filter apparatus preferably further includes a supply line that communicates with an upper part of the filter tank and can supply the liquid to be treated, a residual liquid discharge line that communicates with a lower part of the filter tank and can discharge residual liquid after the treatment, and a purified liquid discharge line that communicates with the one or more filtration membrane modules and can discharge purified liquid after the treatment.

Description

  The present invention relates to a filtration device and an external pressure filtration method.

  2. Description of the Related Art A filtration device having a filtration membrane (see, for example, Japanese Patent Application Laid-Open No. 2010-42329) that mainly transmits only water is used as a filtration device in a sewage treatment or pharmaceutical manufacturing process. The filtration device includes an external pressure type that allows the liquid to be treated to pass through the inside of the filtration membrane by pressurizing the outside of the filtration membrane, negative pressure inside the membrane, osmotic pressure, etc. There is an internal pressure type in which the liquid to be treated is transmitted to the outside of the filtration membrane with a high pressure inside.

JP 2010-42329 A

  Of the above filtration devices, the conventional external pressure filtration device needs to pressurize or suck the liquid to be treated in the filtration tank using, for example, a pump. On the other hand, in the external pressure type filtration device, the surface of the filtration membrane is contaminated due to the adhesion of substances contained in the liquid to be treated with use, so that the filtration capacity is lowered as it is. Therefore, a cleaning method (air scrubbing) is performed in which bubbles are sent from below the filtration membrane module, the surface of each filtration membrane is rubbed, and each filtration membrane is further vibrated to remove deposits.

  As described above, the conventional external pressure type filtration device requires pressure or suction pump power and power for supplying the cleaning bubbles, which contributes to a high processing cost. On the other hand, reduction of processing cost is strongly demanded.

  This invention is made | formed based on the above situations, and it aims at providing the filtration apparatus and external-pressure-type filtration method which are excellent in processing cost.

  The invention made in order to solve the above-mentioned problem has a filtration tank and one or a plurality of filtration membrane modules immersed in the filtration tank, and is an external pressure type that purifies the liquid to be treated supplied into the filtration tank. The filtration device further includes a bubble supplier for supplying bubbles from below the filtration membrane module, and pressurizes the inside of the filtration tank with the bubbles supplied by the bubble supplier.

  Moreover, another invention made | formed in order to solve the said subject uses the external pressure type filtration apparatus which has a filtration tank and 1 or several filtration membrane module immersed in this filtration tank, In the said filtration tank An external pressure filtration method for purifying the liquid to be treated, the method comprising supplying air bubbles from below the filtration membrane module, and pressurizing the inside of the filtration tank with the air bubbles supplied in the step It is.

  The filtration device and the external pressure filtration method of the present invention are excellent in processing cost. Therefore, the filtration apparatus and the external pressure filtration method of the present invention can efficiently separate, for example, a liquid to be treated containing oil or the like.

FIG. 1 is a schematic explanatory view showing a filtration device according to an embodiment of the present invention. FIG. 2 is a schematic explanatory view showing an external pressure filtration method according to an embodiment of the present invention. FIG. 3 is a schematic explanatory view showing an external pressure filtration method according to an embodiment of the present invention. FIG. 4 is a schematic explanatory view showing an external pressure filtration method according to an embodiment of the present invention. FIG. 5 is a schematic explanatory view showing an external pressure filtration method according to an embodiment of the present invention.

[Description of Embodiment of Present Invention]
The invention of the present application is an external pressure type filtration apparatus that has a filtration tank and one or a plurality of filtration membrane modules immersed in the filtration tank, and purifies the liquid to be treated to be supplied into the filtration tank. A bubble supplier for supplying bubbles from below the filtration membrane module is further provided, and the inside of the filtration tank is pressurized by the bubbles supplied by the bubble supplier.

  Since the filtration apparatus pressurizes the inside of the filtration tank with the bubbles supplied from the bubble supply device, the filtration membrane of the filtration membrane module can be washed with the bubbles, and at the same time, the liquid to be treated can pass through the filtration membrane. As a result, the filtration device can downsize or omit the pump that pressurizes the inside of the filtration tank or sucks the inside of the filtration membrane, and thus can significantly reduce the processing cost.

  It is preferable that no other means for pressurizing the inside of the filtration tank is provided. Thus, the pressurization in a filtration tank is performed only with the bubble of a bubble supply device, and the reduction of processing cost can further be accelerated | stimulated.

  It is a cylindrical body in which the filtration tank is erected, and the filtration membrane module may be disposed in the axial direction of the filtration tank. In this way, the filtration tank is set up as a sealable cylindrical body, and the filtration membrane module is disposed in the axial direction of the filtration tank, thereby further enhancing the pressure effect by the bubbles and the cleaning effect of the filtration membrane surface. Can do.

  A supply line that can communicate with the upper part of the filtration tank and supply a liquid to be treated; a residual liquid discharge line that communicates with the lower part of the filtration tank and can discharge the residual liquid after treatment; and the one or more filtration membrane modules And a purification liquid discharge line that is capable of discharging the processed purification liquid. By providing each of such lines, the liquid to be treated can be easily and reliably separated and discharged from the residual liquid and the purification liquid.

  Moreover, this invention uses the external pressure type filtration apparatus which has a filtration tank and 1 or several filtration membrane module immersed in this filtration tank, The external pressure type which purifies the to-be-processed liquid supplied in the said filtration tank A filtration method includes a step of supplying bubbles from below the filtration membrane module, and includes an external pressure filtration method of pressurizing the inside of the filtration tank with bubbles supplied in the step.

  In the external pressure filtration method, the inside of the filtration tank is pressurized with bubbles supplied from the bubble supply device, and thus the filtration membrane of the filtration membrane module can be washed with the bubbles and at the same time, the liquid to be treated can be permeated into the filtration membrane. . As a result, the external pressure filtration method can downsize or omit the pump that pressurizes the inside of the filtration tank or sucks the inside of the filtration membrane, and thus can significantly reduce the processing cost.

[Details of the embodiment of the present invention]
Hereinafter, a filtration device and an external pressure filtration method according to the present invention will be described in detail with reference to the drawings.

<Filtration device>
The filtration device of FIG. 1 includes a filtration tank 1 to which a liquid X to be treated is supplied, one filtration membrane module 2 immersed in the filtration tank 1, and bubbles that supply bubbles from below the filtration membrane module 2. Mainly provided with a feeder 3. Moreover, the said filtration apparatus is the to-be-processed liquid storage tank 4 which stores the to-be-processed liquid X, the purification liquid storage tank 5 which stores the purification liquid Y, the residual liquid storage tank 6 which stores the residual liquid Z, and the filtration tank. 1 to be treated liquid supply line 11 capable of supplying the liquid to be treated X, residual liquid discharge line 12 capable of discharging the residual liquid Z from the filtration tank 1, and purification liquid capable of discharging the purification liquid Y from the filtration membrane module 2. It further includes a discharge line 13, a gas supply line 14 that supplies gas to the bubble supply device 3, and an atmosphere release line 15 that opens the inside of the filter tank 1 to the atmosphere. The said filtration apparatus is a submerged and external pressure type filtration apparatus which purifies the to-be-processed liquid X supplied in the filtration tank 1 with the filtration membrane module 2 immersed in this to-be-processed liquid X. FIG.

  Moreover, the said filtration apparatus is not equipped with the means to pressurize the inside of the filtration tank 1 other than the bubble supply device 3. FIG.

(Filtration tank)
The filtration tank 1 is a container that can store a liquid therein. This filtration tank 1 is a cylindrical body that can be sealed upright. The planar shape of the filtration tank 1 is not specifically limited, For example, it can be set as a circle, a polygon, etc. A filtration membrane module 2 is disposed inside the filtration tank 1 so that the direction of the filtration membrane is aligned with the axial direction of the filtration tank 1. Further, a liquid supply line 11 that can supply the liquid X to be processed is communicated with the upper part of the filtration tank 1, and a residual liquid discharge line 12 that can discharge the residual liquid Z after the treatment is connected to the lower part of the filtration tank 1. Communicate. The liquid to be treated X is supplied to the filtration tank 1 from the liquid tank 4 to be treated via the liquid supply line 11 to be treated, and the residual liquid Z after the treatment in the filtration tank 1 passes through the residual liquid discharge line 12. And discharged to the residual liquid storage tank 6.

  The filtration tank 1 has a detachable lower member 1a at the lower portion (bottom surface portion), and the residual liquid discharge line 12 is connected to the lower member 1a. Moreover, the filtration tank 1 has the upper member 1b which can be removed in the upper part (top | upper surface part). The upper member 1b is integrated with a part of a filtration membrane module 2 described later. The filtration tank 1 is sealed by the lower member 1a and the upper member 1b.

(Filtration membrane module)
The filtration membrane module 2 includes a plurality of filtration membranes arranged in the vertical direction and a holding member that fixes one end or both ends of the plurality of filtration membranes. The filtration membrane may be any filter as long as it allows water to permeate through the inner hollow portion while preventing permeation of the particles of the separation object contained in the liquid to be treated X. For example, a known porous hollow fiber A membrane or a flat membrane element can be used.

  As said hollow fiber membrane, what has a thermoplastic resin as a main component can be used. Examples of the thermoplastic resin include polyethylene, polypropylene, polyvinylidene fluoride, ethylene-vinyl alcohol copolymer, polyamide, polyimide, polyetherimide, polystyrene, polysulfone, polyvinyl alcohol, polyphenylene ether, polyphenylene sulfide, cellulose acetate, and polyacrylonitrile. And polytetrafluoroethylene (PTFE). Among these, PTFE which is excellent in chemical resistance, heat resistance, weather resistance, nonflammability and the like and is porous is preferable, and uniaxially or biaxially stretched PTFE is more preferable. The hollow fiber membrane forming material may be appropriately mixed with other polymers, additives such as lubricants, and the like.

  Further, the hollow fiber membrane preferably has a multilayer structure in order to achieve both water permeability and mechanical strength, and to make the surface cleaning effect due to bubbles effective. Specifically, the hollow fiber membrane preferably includes an inner support layer and a filtration layer laminated on the surface of the support layer.

  The average thickness of the support layer of the hollow fiber membrane is, for example, not less than 0.1 mm and not more than 3 mm. By setting the average thickness of the support layer within the above range, mechanical strength and water permeability can be imparted to the hollow fiber membrane in a well-balanced manner. Moreover, the average thickness of the filtration layer of a hollow fiber membrane is 5 micrometers or more and 100 micrometers or less, for example. By setting the average thickness of the filtration layer within the above range, high filtration performance can be easily and reliably imparted to the hollow fiber membrane.

  The hollow fiber membrane has an average outer diameter of, for example, 2 mm to 6 mm, and an average inner diameter of, for example, 0.5 mm to 4 mm. Moreover, the average length of the hollow fiber membrane can be appropriately designed according to the size and the processing amount of the filtration tank 1.

  As the above flat membrane element, for example, a membrane body made of a resin sheet such as porous PTFE in which a flat membrane is bent and opposed to each other, and polyethylene interposed between the opposing surfaces of this membrane body, etc. A support body made of a resin net and an outer peripheral sealing portion that seals the outer peripheral edge of the film body in a folded state; the bent portion of the film body is disposed below and the opening portion is a header It is possible to use one in which a purification liquid flow path is formed inside by being fixed to.

  The membrane body of the flat membrane element can be a single layer or multiple layers. The membrane body has pores of 0.01 μm or more and 20 μm or less, a particle trapping rate of 90% or more with a particle diameter of 0.45 μm, an average film thickness of 5 μm or more and 200 μm or less, and a fibrous skeleton surrounding the pores. Those having an average maximum length of 5 μm or less are preferred.

  The holding member above the filtration membrane module 2 communicates with the filtration membrane, has a discharge part (water collection header) that collects the liquid that has passed through the filtration membrane, and is integrated with the upper member 1 b of the filtration tank 1. Yes. A purification liquid discharge line 13 capable of discharging the treated purification liquid Y is connected to the discharge unit, and the filtered liquid (purification liquid Y) is discharged from the permeation module 2 by the pressure of the bubbles in the bubble supply unit 3. It is transferred to the cleaning liquid storage tank 5.

  In addition, when the filtration membrane module 2 has a holding member below, this holding member may be integrated with the lower member 1 a of the filtration tank 1.

(Bubble feeder)
The bubble supply device 3 supplies bubbles for cleaning the surface of the filtration membrane and pressurizing the inside of the filtration tank 1 from below the filtration membrane module 2. The bubbles rise while rubbing the surface of the filtration membrane to clean the surface of the filtration membrane and increase the pressure in the sealed filtration tank 1.

  The bubble supplier 3 is immersed in the filtration tank 1 storing the liquid X1 to be treated together with the filtration membrane module 2, and specifically, is disposed in the lower member 1a of the filtration tank 1. The bubble supplier 3 supplies bubbles by continuously or intermittently discharging the gas supplied from the compressor or the like through the gas supply line 14. Such a bubble supply device 3 is not particularly limited, and a known air diffuser can be used. As such an air diffuser, for example, an air diffuser using a porous plate or porous tube in which a large number of holes are formed in a plate or tube made of resin or ceramics, or a jet flow type that jets gas from a diffuser or a sparger Examples include an air diffuser, an intermittent bubble jet diffuser that intermittently jets air bubbles, and the like.

  The gas supplied from the bubble supplier 3 is not particularly limited as long as it is inert, but air is preferably used from the viewpoint of running cost.

  Further, the amount and pressure of bubbles supplied from the bubble supplier 3 can be appropriately designed according to the capacity of the filtration tank 1 and the processing amount per unit time.

(Processed liquid supply line)
The liquid to be processed supply line 11 communicates with the lower part of the liquid tank 4 to be processed and the upper part of the filtration tank 1. A first valve 21 is provided in the liquid supply line 11 to be processed.

(Residual liquid discharge line)
The residual liquid discharge line 12 has one end communicating with the lower part (lower member 1 a) of the filtration tank 1 and the other end opened into the residual liquid storage tank 6. A second valve 22 is provided in the residual liquid discharge line 12.

(Purified liquid discharge line)
The purified liquid discharge line 13 has one end communicating with the filtration membrane module 2 and the other end opened into the purified liquid storage tank 5.

(Gas supply line)
One end of the gas supply line 14 is connected to an air supply source (not shown) such as an air compressor, and the other end is connected to the bubble supply device 3. A third valve 24 is provided in the gas supply line 14. As shown in FIG. 1, the other end of the gas supply line 14 may be connected to the residual liquid discharge line 12 so that the gas supply line 14 and the residual liquid discharge line 12 are partially shared. In this case, the residual liquid Z is discharged through the bubble supplier 3. Further, when the gas supply line 14 and the residual liquid discharge line 12 are partially shared, the second valve 22 and the third valve 24 are provided in non-common parts of the respective lines.

(Open air line)
The air release line 15 is a line for releasing the inside of the filtration tank 1 to the atmosphere when discharging the residual liquid Z in the filtration tank 1 to the residual liquid storage tank 6, and communicates with the upper part of the filtration tank 1. A fourth valve 25 is provided in the atmosphere release line 15. In addition, as shown in FIG. 1, the atmosphere release line 15 may be connected to the liquid supply line 11 to be processed, and the atmosphere release line 15 and the liquid supply line 11 to be processed may be partially shared. In this case, the first valve 21 and the fourth valve 25 are provided in a non-common part of each line.

<Advantages>
Since the filtration apparatus pressurizes the inside of the filtration tank 1 with bubbles supplied from the bubble supply device 3, the filtration membrane of the filtration membrane module 2 is washed with the bubbles, and at the same time, the liquid X to be treated is permeated into the filtration membrane 1. be able to. Therefore, since the said filtration apparatus can perform a water treatment with high efficiency, without using the pump which pressurizes the inside of the filtration tank 1, or attracts | sucks the inside of the filtration membrane 1, it can reduce processing cost remarkably.

  Moreover, since the said filtration apparatus makes the filter tank 1 stand-up-sealable cylindrical body and arrange | positions the filtration membrane module 2 to the axial direction of the filtration tank 1, the pressurization effect by a bubble and the filtration membrane surface The cleaning effect can be further enhanced.

  Furthermore, the filtration apparatus includes a liquid supply line 11 to be processed to which a liquid X to be processed can be supplied, a residual liquid discharge line 12 that is communicated with the lower part of the filtration tank 1 and can discharge a residual liquid Z after processing, Since it is provided with a purification liquid discharge line 13 that communicates with the module 2 and can discharge the processed purification liquid Y, the liquid X to be treated can be easily and reliably separated into the residual liquid Z and the purification liquid Y and discharged. Can do.

<External pressure filtration method>
The external pressure filtration method uses an external pressure filtration device having a filtration tank and one filtration membrane module immersed in the filtration tank, and purifies the liquid to be treated supplied into the filtration tank. Hereinafter, an embodiment of the external pressure filtration method will be described using the filtration device of FIG. 1 described above.

The external pressure filtration method includes the following steps.
(1) A process of supplying the liquid X to the filtration tank 1 (liquid supply process)
(2) Step of supplying bubbles from below the filtration membrane module 2 (bubble supply step)
(3) A step of discharging the treated residual liquid Z from the filtration tank 1 (residual liquid discharging step)

(Processed liquid supply process)
In the process liquid supply step, the process liquid X is supplied from the process liquid storage tank 4 to the filtration tank 1 through the process liquid supply line 11 as shown in FIG. That is, by opening the first valve 21 and closing the remaining valves (the second valve 22, the third valve 24, and the fourth valve 25), the liquid X to be processed is removed by gravity from the liquid tank 4 to be processed. Is transferred into the filtration tank 1. Note that the liquid X to be processed may be transferred using a pump or the like. Moreover, after the to-be-processed liquid X is filled in the filtration tank 1, the 1st valve 21 is closed.

(Bubble supply process)
In the bubble supply step, as shown in FIG. 3, bubbles B are supplied from below the filtration membrane module 2 by the bubble supplier 3 in the filtration tank 1 to which the liquid X to be treated is supplied. At this time, the third valve 24 is opened, and the remaining valves (the first valve 21, the second valve 22, and the fourth valve 25) are closed. Thereby, the inside of the filtration tank 1 is pressurized, the liquid X to be treated penetrates into the filtration membrane of the filtration membrane module 2, and the purification solution Y passes through the purification solution discharge line 13 as shown in FIG. It is discharged to the tank 5.

(Residual liquid discharge process)
In the residual liquid discharging step, as shown in FIG. 4, the residual liquid Z, which is the liquid X to be processed remaining in the filtration tank 1 after the processing, is discharged to the residual liquid storage tank 6 by opening to the atmosphere. That is, by opening the second valve 22 and the fourth valve 25 and closing the remaining valves (first valve 21 and third valve 24), the inside of the filtration tank 1 is opened to the atmosphere, as shown in FIG. The residual liquid Z is discharged to the residual liquid storage tank 6 through the residual liquid discharge line 12 by gravity.

  After the residual liquid discharge process, the liquid X to be processed can be sequentially purified by repeating the above steps again in order from the liquid supply process. The residual liquid discharge step does not have to be performed every time after the bubble supply step, and may be performed according to the amount of the residual liquid Z.

  The purified liquid Y purified by the external pressure filtration method is stored in the purified liquid storage tank 5 and the residual liquid Z is stored in the residual liquid storage tank 6. These purification liquid Y and residual liquid Z are used or disposed of by appropriate methods.

  Specific applications of the external pressure filtration method include, for example, sewage treatment, industrial wastewater treatment, industrial tap water filtration, washing water treatment for machinery, pool water filtration, river water filtration, seawater filtration, and fermentation process removal. Bacteria or turbidity (enzyme or amino acid purification), filtration of food, liquor, beer, wine, etc. (especially raw products), separation of bacterial cells from fermenters in pharmaceuticals, filtration of water and dissolved dyes in the dyeing industry, animal cells Culture filtration, pretreatment filtration in pure water production process (including seawater desalination) in RO membrane, pretreatment filtration in ion exchange membrane process, pretreatment filtration in pure water production process using ion exchange resin Etc.

  In the water purification treatment, the filtration device can be used in combination with powdered activated carbon. First, very fine dissolved organic matter is adsorbed by powdered activated carbon, and water containing the powdered activated carbon after adsorbing the dissolved organic matter is filtered by the filtration device, whereby water purification can be performed efficiently.

  In sewage treatment, it can be used in combination with a tank in which cells are propagated. After sewage is introduced into this tank and the bacterial cells decompose and clean the contaminated components in the sewage, sewage treatment can be performed efficiently by filtering the sewage containing the bacterial cells with the filtration device. .

[Other Examples]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not limited to the configuration of the embodiment described above, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. The

  In the above embodiment, one filtration membrane module is arranged in one filtration tank, but a plurality of filtration membrane modules may be arranged in one filtration tank.

  Moreover, the said filtration apparatus may have another means to pressurize the inside of a filtration tank in addition to a bubble supply device. Thus, even when other pressurizing means (for example, a pressurizing pump) is provided, the filtration device pressurizes the inside of the filtration tank with the bubble supply device, so that the capacity of the pressurizing pump or the like is reduced to reduce the processing cost. Can be achieved.

  Furthermore, if the shape of the filtration tank used for the said filtration apparatus can maintain a sealed state, it will not be limited to a cylindrical body. Moreover, when using a cylindrical body as a filtration tank, the filtration tank may be disposed sideways (in which the axis is horizontal), or the filtration membrane module may be disposed in a direction other than the axial direction of the filtration tank. Good.

  Moreover, the connection position and the number of each line connected to the filtration tank of the said filtration apparatus are not limited to what was demonstrated by the said embodiment, A design change is possible suitably. For example, the liquid supply line to be processed may be connected below the filtration tank.

  Further, in the above embodiment of the external pressure filtration method, the supply of the liquid to be processed and the supply of bubbles are sequentially switched, but the supply of bubbles is continuously performed while the liquid to be processed is continuously supplied. The filtration process may be carried out continuously.

  As described above, the filtration device and the external pressure filtration method of the present invention are excellent in processing cost. Accordingly, the filtration device and the external pressure filtration method can be suitably used in various fields as a solid-liquid separation treatment device.

DESCRIPTION OF SYMBOLS 1 Filtration tank 1a Lower member 1b Upper member 2 Filtration membrane module 3 Bubble supply device 4 Processed liquid storage tank 5 Purified liquid storage tank 6 Residual liquid storage tank 11 Processed liquid supply line 12 Residual liquid discharge line 13 Purified liquid discharge line 14 Gas supply line 15 Atmospheric release line 21 First valve 22 Second valve 24 Third valve 25 Fourth valve X Liquid to be treated Y Purified liquid Z Residual liquid

Claims (5)

An external pressure type filtration device that has a filtration tank and one or a plurality of filtration membrane modules immersed in the filtration tank, and purifies the liquid to be treated supplied into the filtration tank,
A bubble feeder for supplying bubbles from below the filtration membrane module;
The filtration apparatus which pressurizes the inside of the said filtration tank with the bubble which the said bubble supply device supplies.   The filtration apparatus according to claim 1, wherein no other means for pressurizing the inside of the filtration tank is provided. It is a sealable cylindrical body in which the filtration tank is erected,
The filtration apparatus according to claim 1 or 2, wherein the filtration membrane module is disposed in an axial direction of the filtration tank. A supply line communicating with the upper part of the filtration tank and capable of supplying a liquid to be treated;
A residual liquid discharge line that communicates with the lower part of the filtration tank and can discharge the residual liquid after treatment;
The filtration device according to claim 1, 2 or 3, further comprising: a purification liquid discharge line communicating with the one or more filtration membrane modules and capable of discharging the processed purification liquid. An external pressure filtration method for purifying a liquid to be treated to be supplied into the filtration tank using an external pressure type filtration apparatus having a filtration tank and one or a plurality of filtration membrane modules immersed in the filtration tank,
Supplying air bubbles from below the filtration membrane module,
External pressure filtration method in which the inside of the filtration tank is pressurized with bubbles supplied in the above process

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