Bag filter device and powder adsorbent recovery system using the same

Abstract

To provide a bag filter device that can perform dehydration treatment with high efficiency even on waste adsorbent sludge with high water content without slowing down a filtration rate.SOLUTION: A bag filter device comprises: a storage tank that stores powder adsorbent-containing slurry; a bag filter that is supplied with the powder adsorbent-containing slurry by a transfer pump installed in the middle of a pipe, and causes the powder adsorbent-containing slurry to flow through a plurality of filter elements installed therein to filter the slurry; an air compressor that supplies air to remove a cake on the surfaces of the plurality of filter elements formed by the powder adsorbent-containing slurry flowing through the filter elements and being filtered, from the surfaces of the filter elements by air backwash; a sludge recovery container that is installed below the bag filter and recovers the cake removed by the air supplied from the air compressor; and a control unit that controls the amount of the powder adsorbent-containing slurry supplied by the transfer pump so that the thickness of the cake formed on the surfaces of the filter elements becomes equal to or less than a predetermined thickness.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a bag filter device and a powder adsorbent recovery system using the same, and more particularly to a bag filter device suitable for treating sludge generated by treating contaminated water in a nuclear power plant using a bag filter, and a powder adsorbent recovery system using the same.

Background Art

[0002] During the operation of removing fuel debris in a nuclear power plant, it is assumed that a large amount of waste such as slurry and / or sludge containing a large amount of α-radioactivity will be generated. In particular, there is concern that waste adsorbent sludge with a very high water content will be generated by treating contaminated water using a powder adsorbent, and equipment capable of highly efficient dehydration treatment is required.

[0003] As a sludge dehydration treatment technology, a method using a bag filter has been considered, and currently, development is underway regarding its applicability to the above-mentioned waste adsorbent sludge.

[0004] By the way, the contaminated water generated during the operation of removing fuel debris in a nuclear power plant, and the problems generated by its treatment are as follows. (1) The contaminated water generated during the operation of removing fuel debris in a nuclear power plant generally has different properties from the low-radioactivity-level contaminated water generated from the nuclear site, contains a large amount of various α substances derived from fuel debris, and has a high radioactivity concentration. (2) The sludge generated by treating the contaminated water in a nuclear power plant is generated in a very large amount and has a very high water content. However, since the storage space within the nuclear power plant site is limited, highly efficient dehydration treatment is required.

[0005] For this reason, as a dehydration treatment of sludge, dehydration treatment by filtration for separating particles using a filter is performed.

[0006] Incidentally, Patent Document 1 describes a washing waste liquid filtration device in which, in order to improve the dischargeability by reducing the activated carbon peeled from the filtration membrane into small blocks, a plurality of filter elements having a hollow cylindrical shape are erected in a treatment container, and a treatment waste liquid supply pipe for supplying a treatment waste liquid in which granular activated carbon is added to the washing waste liquid is connected in the treatment container, and a purified water discharge pipe for discharging the purified water treated by the filter element is connected. Further, a peeling air supply source for supplying peeling air from this purified water discharge pipe into the filter element to peel the used granular activated carbon adhering to the outer surface is connected, and fins for dividing the granular activated carbon adhering to the outer peripheral surface of each filter element into a plurality of small blocks are provided. A washing waste liquid filtration device is described.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] By the way, it is known that in the dehydration treatment by the above-described filtration, the equipment differential pressure during filtration increases as the particle size becomes finer, and the dehydration treatment becomes difficult. The waste adsorbent sludge to be dehydrated is mainly composed of fine particles on the order of several μm, and there is a problem that the filtration rate significantly decreases when the cake thickness formed on the filter surface is large.

[0009] The problems in the case of dehydrating the waste adsorbent sludge by filtration are described below. (A) When the cake thickness is large, the water permeability is low, the filtration rate is slow, and a long treatment time is required. (B) In a device configuration in which the sludge storage container and the filter element are integrated, the dead space becomes large and the sludge filling rate becomes low. As the cake formed as the filtration process proceeds adheres to the surface of the filter element, it becomes difficult to discharge the sludge by air backwashing. (D) For a powdered adsorbent in which nuclide detachment occurs when immersed for a long time, it is desirable to remove it by short-time filtration, but it is difficult to maintain a high filtration rate and perform the filtration process.

[0010] However, Patent Document 1 described above does not describe any solutions for solving the problems (A) - (D) described above.

[0011] The present invention has been made in view of the above points, and an object thereof is to provide a bag filter device capable of highly efficient dehydration treatment without a decrease in filtration rate even for waste adsorbent sludge with a high water content, and a powder adsorbent recovery system using the same.

Means for Solving the Problems

[0012] The bag filter device of the present invention, in order to achieve the above object, includes a storage tank for storing a slurry containing a powdered adsorbent, the slurry containing the powdered adsorbent from the storage tank is supplied by a transfer pump installed in the middle of a pipe, and a bag filter in which a plurality of filter elements installed inside are passed through by the slurry containing the powdered adsorbent for filtration, an air compressor for supplying air for peeling off the cake formed on the surface of the filter element by air backwashing when the slurry containing the powdered adsorbent passes through and filters through the plurality of filter elements, a sludge recovery container installed below the bag filter for recovering the cake peeled off by the air supplied from the air compressor, and a control device for controlling the supply water flow rate of the slurry containing the powdered adsorbent in the transfer pump so that the thickness of the cake formed on the surface of the filter element becomes equal to or less than a predetermined thickness.

[0013] In addition, in order to achieve the above object, the powder adsorbent recovery system of the present invention includes a storage tank that stores a slurry containing a powder adsorbent and performs an adsorption treatment for nuclide removal using the powder adsorbent, and an adsorption material suspension generated by the adsorption treatment in the storage tank is supplied. A concentration device that concentrates the adsorption material suspension by leaching moisture from a cross filter installed inside, a sedimentation separation device that is supplied with the concentrated water concentrated by the concentration device and separates the concentrated water into supernatant water and sludge, and a bag filter device that filters the sludge sedimentation-separated by the sedimentation separation device. The bag filter device is characterized in that it is the bag filter device of the present invention having the above configuration.

Advantages of the Invention

[0014] According to the present invention, even for waste adsorbent sludge with a high water content, the filtration rate does not decrease and high-efficiency dehydration treatment becomes possible.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2(a)

Figure 2(b)

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0016] Hereinafter, a bag filter device of the present invention and a powder adsorbent recovery system using the same will be described based on the illustrated embodiments. In each figure, the same reference numerals are used for the same components.

Example

[0017] FIG. 1 shows Example 1 of the bag filter device of the present invention.

[0018] As shown in FIG. 1, the bag filter device 1 of this embodiment includes a powder adsorbent-containing slurry storage tank 2 that stores the powder adsorbent-containing slurry supplied from the first pipe 10, and the powder adsorbent-containing slurry from this powder adsorbent-containing slurry storage tank 2 is supplied by a waste liquid transfer pump 23 installed in the middle of the second pipe 11, and a bag filter 3 in which the powder adsorbent-containing slurry passes through and filters a plurality of filter elements 4 installed inside, and a plurality of filter elements 4 pass through and filter the powder adsorbent-containing slurry, so that the cake (see FIG. 2(a)) formed on the surface of the filter element 4 is removed from the surface of the filter element 4 by air backwashing. An air compressor 9 that supplies air for this purpose, a sludge recovery container 6 installed below the bag filter 3 that recovers the cake peeled off by air backwashing with the air supplied from the air compressor 9, and a control device 24 that controls the supply water flow rate of the powder adsorbent-containing slurry in the waste liquid transfer pump 23 so that the thickness of the cake formed on the surface of the filter element 4 becomes equal to or less than a predetermined thickness. It is roughly composed of

[0019] Further, a filter aid feeder 7 for supplying a filter aid is connected to the slurry storage tank 2 containing the powder adsorbent via a third pipe 14, a precoat material feeder 8 for supplying a precoat material is connected to the bag filter 3 via a fourth pipe 15, and a sludge recovery container 6 is connected to the bag filter 3 via a gate valve 5.

[0020] Also, an air compressor 9 is connected to the bag filter 3 via a fifth pipe 16 in which a valve 22 is installed in the middle and a sixth pipe 12. The treated water treated by the bag filter 3 is discharged via the sixth pipe 12, and the residual water remaining in the bag filter 3 is returned to the slurry storage tank 2 containing the powder adsorbent via a seventh pipe 13.

[0021] A valve 17 is installed in the second pipe 11 described above, a valve 20 is installed in the third pipe 14, a valve 21 is installed in the fourth pipe 15, a valve 18 is installed in the sixth pipe 12, and a valve 19 is installed in the seventh pipe 13, respectively.

[0022] Note that as the filter aid supplied by the filter aid feeder 7 and the precoat material supplied by the precoat material feeder 8, a fibrous silicate mineral is preferable.

[0023] Next, a cake recovery method using the bag filter device 1 will be described, in which the cake formed on the surface of the filter element 4 is peeled off from the surface of the filter element 4 by air backwashing with air supplied from the air compressor 9, and the peeled cake is recovered by a sludge recovery container 6 installed below the bag filter 3.

[0024] That is, the powder adsorbent-containing slurry from the powder adsorbent-containing slurry storage tank 2 is supplied to the bag filter 3 by the waste liquid transfer pump 23 installed in the middle of the second pipe 11, and the powder adsorbent-containing slurry passes through a plurality of filter elements 4 installed inside the bag filter 3 for filtration. The cake formed on the surface of the filter element 4 by this filtration (the upper state in Fig. 2(a)) is peeled off from the surface of the filter element 4 by air backwashing with the air supplied from the air compressor 9 (the lower state in Fig. 2(a)). When the peeled cake is recovered by the sludge recovery container 6 installed below the bag filter 3, the thickness of the cake formed on the surface of the filter element 4 is set to a cake thickness that is controlled by the control device 24 to be below a predetermined thickness when the supply water flow rate of the powder adsorbent-containing slurry in the waste liquid transfer pump 23 is controlled. The cake of this thickness is peeled off from the surface of the filter element 4 by air backwashing with the air supplied from the air compressor 9, and the peeled cake is recovered by the sludge recovery container 6 (the state in Fig. 2(b)).

[0025] Specifically, when solid-liquid separating a powder adsorbent-containing slurry containing a silicate-based adsorbent such as sodium titanate or crystalline silicotitanate with a particle size of several μm, the control device 24 controls the supply water flow rate of the waste liquid transfer pump 23 so that the thickness of the cake formed on the surface of the filter element 4 is below the cake thickness derived by the following formula (1).

[0026] On the other hand, when solid-liquid separating a powder adsorbent-containing slurry containing an activated carbon-based adsorbent or an iron oxide-based adsorbent with a particle size of several tens of μm, the control device 24 controls the supply water flow rate of the waste liquid transfer pump 23 so that the thickness of the cake formed on the surface of the filter element 4 is below the cake thickness derived by the following formula (2).

[0027] y1 [mm]=-6.5lnX1 - 25···(1) ln represents the natural logarithm (the same applies to the following descriptions).

[0028] Here, X1 [ml / min / mm 2=a [ml] / b [min] / c [mm 2 (a: processing liquid volume [ml], b: processing time [min], c: filtration area [mm 2 y2 [mm]= -5.9 ln X2 - 9.1 ··· (2) Here, X2 [ml / min / mm 2 =a [ml] / b [min] / c [mm 2 (a: processing liquid volume [ml], b: processing time [min], c: filtration area [mm 2 Note that the interval between the plurality of filter elements 4 installed inside the bag filter 3 is preferably larger than the cake thickness obtained by the above formula (1) or the above formula (2).

[0029] Next, the calculation of the upper limit value of the appropriate cake thickness will be described.

[0030] When using powdered sodium titanate or crystalline silicotitanate with a particle size of several μm, the average filtration rate per unit area is X1 [ml / min / mm 2 When, the appropriate cake thickness y1 is represented by formula (1).

[0031] y1 [mm]= -6.5 ln X1 - 25 ··· (1) On the other hand, when using an activated carbon-based adsorbent with a particle size of several tens of μm, the average filtration rate per unit area is X2 [ml / min / mm 2 When, the appropriate cake thickness y2 is represented by formula (2).

[0032] y2 [mm]= -5.9 ln X2 - 9.1 ··· (2) Control the water flow rate for one batch (one cycle of the treatment cycle) of the powdered adsorbent slurry so that the cake thickness formed on the surface of the filter element 4 is controlled within the range of the appropriate value of the above formula. Also, the interval between the filter elements 4 is made sufficiently larger than the cake thickness. However, the average filtration rate X per unit area is calculated by the following formula.

[0033] X [ml / min / mm 2 ​​=a [ml] / b [min] / c [mm 2 (a: Processing liquid volume [ml], b: Processing time [min], c: Filtration area [mm 2 ) [Application Example 1] Since most off-the-shelf filter elements are about Φ70mm, calculations were made assuming Φ70mm × H500mm × 3 pieces. The filtration area of each is about 0.33E+ [mm 2 .

[0034] Since the required processing flow rate in one nuclear power plant installed in the country is set at 220 L / day, when the processing liquid volume is 220×10^3 [mL] and the processing time is 24×60 [min], the upper limit values of the appropriate cake thickness are calculated as follows respectively.

[0035] ∴ y1 [mm]=24.9 [mm] ∴ y2 [mm]=36.2 [mm] Next, the test conducted to evaluate the appropriate cake thickness will be described with reference to Figure 3.

[0036] As shown in Figure 3, the test apparatus pressurizes the powdered adsorbent with air supplied from an air compressor connected via a connecting pipe to a supply tank storing moisture + powdered adsorbent (and a flocculant is also added in some tests), and filters it through the filter element.

[0037] Specifically, using the test apparatus in Figure 3, a test was conducted to filter the powdered adsorbent from the waste liquid containing the powdered adsorbent. Two types of powdered adsorbents, crystalline silicotitanate and attached activated carbon, were used, and other test parameters such as the addition concentration of the powdered adsorbent and the addition concentration of the flocculant were set.

[0038] Waste liquid was supplied to the supply tank at the upper part of Fig. 3, and pressure filtration was carried out with air supplied from an air compressor. The moisture contained in the waste liquid permeated through the filter element and was collected in the permeated water receiving tank installed at the lower part of Fig. 3. The powdered adsorbent accumulated on the surface of the filter element to form a cake. As the test time elapsed, the cake gradually grew thicker, and it was confirmed that the thicker the cake thickness, the worse the moisture permeability.

[0039] From this test, measurement data of the cake thickness and the average filtration rate (the amount of permeated water through the filter element / treatment time) for each test case were obtained, and the correlation between the cake thickness and the average filtration rate was evaluated.

[0040] A list of the obtained test results is shown in Fig. 4.

[0041] Note that the average filtration rate was calculated as the average filtration rate per unit area (the following formula) by dividing by the filtration area of the filter element.

[0042] Average filtration rate per unit area [ml / min / mm 2 =Average filtration rate [ml / min] / Filtration area of the filter element [mm 2 The relationship between the cake thickness and the average filtration rate per unit area obtained from the test results is shown in Fig. 5. Also shown are the results of obtaining an approximate curve using the least squares method for each powdered adsorbent.

[0043] The equations of the approximate curves evaluated from Fig. 5 (where y1 and y2 represent the cake thickness, and X1 and X2 represent the average filtration rate per unit area) are as follows: When using crystalline silicotitanate, y1 [mm]= -6.5lnX1 - 25 ··· (1) When using an activated carbon-based adsorbent, y2 [mm]= -5.9lnX2 - 9.1 ··· (2) X [ml / min / mm 2 =a [ml] / b [min] / c [mm 2 (a: amount of treatment liquid [ml], b: treatment time [min], c: filtration area [mm​2 ) Examples of application for evaluating the appropriate cake thickness are described below. [Example of Application 2] When the type of the powder adsorbent is crystalline silicotitanate, the SS concentration of the waste liquid is 10,000 ppm, the volume of the waste liquid is 1 m 3 , the treatment time is within 10 h, and the filtration area of the filter element is 1.0E+06 mm 2 , the average filtration rate per unit area required is X1 = (1.0E+06 ml) ÷ (10 h × 60 min / h) ÷ (1.0E+06 mm 2 ) ≈ 1.7E-03 ml / min / mm 2 becomes.

[0044] Therefore, from the local curve (indicated by the ○ mark) of the crystalline silicotitanate in Fig. 5, the appropriate cake thickness is evaluated to be about 16.5 mm. [Example of Application 3] When the type of the powder adsorbent is an activated carbon-based adsorbent, the SS concentration of the waste liquid is 10,000 ppm, the volume of the waste liquid is 300 L, the treatment time is within 24 h, and the filtration area of the filter element is 1.0E+05 mm 2 , the average filtration rate per unit area required is X2 = (3.0E+05 ml) ÷ (24 h × 60 min / h) ÷ (1.0E+056 mm 2 ) ≈ 2.1E-03 ml / min / mm 2 becomes.

[0045] Therefore, from the local curve (indicated by the ● mark) of the activated carbon-based adsorbent in Fig. 5, the appropriate cake thickness is evaluated to be about 27.3 mm.

[0046] According to the bag filter device of the present embodiment and the cake recovery method using the same described above, even for waste adsorbent sludge with a high water content, the filtration rate does not decrease and high-efficiency dehydration treatment is possible. That is, only the solid component can be recovered into the sludge recovery container 6, so that the sludge can be recovered in a state with a high sludge filling rate, and since the filtration treatment can be performed within an appropriate range of the cake thickness, continuous treatment can be performed at a high filtration rate.

[0047] Furthermore, by using auxiliary agents (precoat agents, filter aids), it becomes possible to enhance the cake releasability, improve the recoverability of the particles trapped by the filter element 4, increase the efficiency of air backwashing, prevent the spread of contamination due to scattering, and moreover, by separating the powdered adsorbent from the early treatment system, it becomes possible to suppress the possibility of the adsorbed radionuclides desorbing.

Examples

[0048] Although not particularly shown, as Example 2 of the present invention, a cake recovery method using a bag filter device will be described, in which a slurry containing a powdered adsorbent resulting from adsorbing and removing α nuclides contained in radioactive waste liquid using a powdered adsorbent is subjected to solid-liquid separation, and the same bag filter device 1 as in Example 1 is used to peel and recover the cake formed on the surface of the filter element 4 constituting this bag filter device 1.

[0049] The cake recovery method using the bag filter device of this example uses a bag filter for recovering the powdered adsorbent from the slurry containing the powdered adsorbent, an air compressor for supplying air for peeling the cake formed on the surface of the filter element installed in this bag filter by air backwashing, and a sludge recovery container installed below the bag filter for recovering the cake discharged by air backwashing with the air supplied from the air compressor at the lower part, and by passing the slurry containing the powdered adsorbent through the bag filter, the powdered adsorbent is recovered, the cake formed on the surface of the filter element is peeled by air backwashing with the air supplied from the air compressor, and is recovered in the sludge recovery container.

[0050] Specifically, when solid-liquid separating a slurry containing a powdered adsorbent containing a silicate-based adsorbent such as sodium titanate or crystalline silicotitanate with a particle size of several μm, the control device controls the supply water flow rate of the waste liquid transfer pump so that the thickness of the cake formed on the surface of the filter element is not more than the cake thickness derived from the following formula (1).

[0051] On the other hand, when solid-liquid separating a powder adsorbent-containing slurry containing an activated carbon-based adsorbent or an iron oxide-based adsorbent with a particle size of several tens of μm, the control device controls the supply water flow rate of the waste liquid transfer pump so that the thickness of the cake formed on the surface of the filter element is equal to or less than the cake thickness derived from the following formula (2).

[0052] y1 [mm]= -6.5lnX1 - 25 ··· (1) Here, X1 [ml / min / mm 2 = a [ml] / b [min] / c [mm 2 (a: treatment liquid volume [ml], b: treatment time [min], c: filtration area [mm 2 y2 [mm]= -5.9lnX2 - 9.1 ··· (2) Here, X2 [ml / min / mm 2 = a [ml] / b [min] / c [mm 2 (a: treatment liquid volume [ml], b: treatment time [min], c: filtration area [mm 2 Even in such this Example, the effect is the same as that of Example 1.

Example

[0053] As Example 3 of the present invention, a powder adsorbent recovery system using the above-described bag filter device 1 and its powder adsorbent recovery method will be described.

[0054] A powder adsorbent recovery system using the bag filter device 1 of this Example is shown in FIG. 6.

[0055] ​​As shown in Fig. 6, the powder adsorbent recovery system 25 of this embodiment stores the powder adsorbent-containing slurry supplied through the first pipe 33, and performs an adsorption treatment for nuclide removal with the powder adsorbent in the waste liquid storage tank 26. The adsorbent suspension generated by the adsorption treatment in the waste liquid storage tank 26 is supplied through the second pipe 34 by the submersible pump 32 installed inside the waste liquid storage tank 26, and the cross-flow concentration device 27 that concentrates the adsorbent suspension by leaching moisture from the cross-flow filter element 28 installed inside. The concentrated water concentrated by the cross-flow concentration device 27 is supplied to the sedimentation separation device 29 that sedimentation-separates the concentrated water into supernatant water and sludge, and the bag filter device 1 having the configuration described in Example 1 that filters the sludge sedimentation-separated by the sedimentation separation device 29. It is roughly configured from.

[0056] In addition, the waste liquid storage tank 26 and the sedimentation separation device 29 are connected through the fourth pipe 36, and the sedimentation separation device 29 is supplied with a flocculant for performing a flocculation precipitation treatment through the fifth pipe 37 and a water quality adjustment reagent through the sixth pipe 38. The water quality adjustment reagent supply device 31 is connected respectively.

[0057] In addition, a waste liquid transfer pump 47 for transferring the waste liquid containing sludge is installed in the middle of the seventh pipe 39 connecting the sedimentation separation device 29 and the bag filter device 1, and the water flow rate of the waste liquid to the bag filter device 1 is controlled by the control device 48. The adsorbed treated water in the bag filter device 1 is discharged from the bag filter device 1 through the ninth pipe 41.

[0058] In addition, the adsorbed treated water treated by the cross-flow concentration device 27 is discharged through the eighth pipe 40, and further, the third pipe 35 is connected to the bottom of the cross-flow concentration device 27, and the untreated suspension is discharged through this third pipe 35. It is designed to be returned to the waste liquid storage tank 26.

[0059] In addition, a valve 42 is installed in the above-described second pipe 34, a valve 43 is installed in the third pipe 35, a valve 44 is installed in the fourth pipe 36, a valve 45 is installed in the seventh pipe 39, and a valve 46 is installed in the eighth pipe 40, respectively.

[0060] The powder adsorbent is preferably any one of sodium titanate, crystalline silicon titanate, attached activated carbon, and iron oxide.

[0061] Next, a method for recovering the powder adsorbent using the bag filter device 1 of the present embodiment will be described with reference to FIGS. 6 and 7.

[0062] As shown in the figure, the method for recovering the powdered adsorbent using the bug filter device 1 of the present embodiment includes a first step (S1) of performing an adsorption treatment for nuclide removal in the waste liquid storage tank 26 with the powdered adsorbent, a second step (S2) of discharging the suspension of the powdered adsorbent into the cross-flow filter concentration system with the submersible pump 32 after performing the adsorption treatment in the waste liquid storage tank 26 for a predetermined time, a third step (S3) of circulating the cross-flow filter concentration system and performing a concentration treatment by leaching moisture from the cross-flow filter element 28 with the cross-flow concentration device 27, a fourth step (S4) of discharging the cross-flow concentrated water into the sedimentation separation device 29 after performing the concentration treatment with the cross-flow concentration device 27 for a predetermined time, a fifth step (S5) of adding a flocculant to the sedimentation separation device 29 to perform a flocculation sedimentation treatment, allowing it to stand for a predetermined time, and separating it into supernatant water and sediment sludge, a sixth step (S6) of extracting and removing the supernatant water with a second pump (a pump (not shown) installed in the sedimentation separation device 29), a seventh step (S7) of discharging the sediment sludge remaining in the sedimentation separation device 29 into a buffer tank in the bug filter device 1 (this buffer tank does not directly transfer the sludge from the sedimentation separation device 29 to the bug filter device 1, but instead installs a buffer tank in between, stores it in the buffer tank to a certain extent, and then transfers it to the bug filter device 1. It is not shown in Fig. 6 and corresponds to the powdered adsorbent-containing slurry storage tank 2 in Fig. 1), an eighth step (S8) of passing a suspension of the precoat agent through the bug filter device 1 to form a precoat agent cake on the surface of the filter element 4 in the bug filter device 1, a ninth step (S9) of adding a filter aid to the buffer tank and mixing it with the stored sediment sludge by stirring, a tenth step (S10) of passing the sediment sludge stored in the buffer tank through the filter element 4 for filtration treatment, an eleventh step (S11) of ending the water passing treatment when the cake thickness on the surface of the filter element 4 exceeds a predetermined range, a twelfth step (S12) of discharging the liquid in the system from the drain line and returning it to the previous buffer tank, a thirteenth step (S13) of opening the gate valve 5 installed between the bug filter 3 and the sludge recovery container 6 in the bug filter device 1, a fourteenth step (S14) of starting the air compressor 9 and supplying air from the air compressor 9 to the bug filter device 1 to perform an air backwash,In a 15th step (S15), the sludge peeled off from the surface of the filter element 4 by air backwashing with air supplied from the air compressor 9 is received by the sludge collection container 6, and then the gate valve 5 is closed. In a 16th step (S16), steps S8 to S15 are repeatedly performed a plurality of times, and when the sludge filling rate in the sludge collection container 6 reaches a predetermined value, the sludge is discharged. This is the gist of the present invention.

[0063] Further, the sludge collection container 6 in this embodiment is of a cartridge type. After the discharge of the sludge collection container 6 is completed, a new sludge collection container is installed, and the dehydration treatment is performed by steps S1 to S15.

[0064] Even in the powder adsorbent recovery system and its powder adsorbent recovery method using the bag filter device 1 of this embodiment, even if the waste adsorbent sludge has a high water content, the filtration rate does not decrease and the dehydration treatment can be performed with high efficiency.

[0065] Note that the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, it is possible to add the configuration of another embodiment to a part of the configuration of one embodiment. Further, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

Explanation of Reference Numerals

[0066] 1… Bug filter device, 2… Slurry storage tank containing powder adsorbent, 3… Bug filter, 4… Filter element, 5… Gate valve, 6… Sludge recovery container, 7… Filter aid feeder, 8… Precoat material feeder, 9… Air compressor, 10, 33… First pipe, 11, 34… Second pipe, 12, 38… Sixth pipe, 13, 39… Seventh pipe, 14, 35… Third pipe, 15, 36… Fourth pipe, 16, 37… Fifth pipe, 17, 18, 19, 20, 21, 22, 42, 43, 44, 45, 46… Valve, 23, 47… Waste liquid transfer pump, 24, 48… Control device, 25… Powder adsorbent recovery system using bug filter device, 26… Waste liquid storage tank, 27… Crossflow concentration device, 28… Crossflow filter element, 29… Sedimentation separation device, 30… Coagulant feeder, 31… Water quality adjustment reagent feeder, 32… Submersible pump, 40… Eighth pipe, 41… Ninth pipe.

Claims

1. A storage tank for storing a slurry containing a powder adsorbent, a transfer pump installed in the middle of a pipe through which the slurry containing the powder adsorbent from the storage tank is supplied, and a plurality of filter elements installed inside, through which the slurry containing the powder adsorbent passes through and is filtered, a bag filter, an air compressor for supplying air for peeling off a cake formed on the surface of the filter element by air backwashing when the slurry containing the powder adsorbent passes through and filters a plurality of the filter elements, a sludge recovery container installed below the bag filter for recovering the cake peeled off by the air supplied from the air compressor, and a control device for controlling the supply water flow rate of the slurry containing the powder adsorbent in the transfer pump so that the thickness of the cake formed on the surface of the filter element is equal to or less than a predetermined thickness. A bag filter device characterized by comprising.

2. The bag filter device according to claim 1, wherein When solid-liquid separation of the slurry containing the powder adsorbent containing a silicate-based adsorbent is performed, the control device controls the supply water flow rate of the transfer pump so that the thickness of the cake is equal to or less than the cake thickness derived from the following formula (1), or Alternatively, when solid-liquid separation of the slurry containing the powder adsorbent containing an activated carbon-based adsorbent or an iron oxide-based adsorbent is performed, the control device controls the supply water flow rate of the transfer pump so that the thickness of the cake is equal to or less than the cake thickness derived from the following formula (2). A bag filter device characterized by this. y1 [mm] = -6.5 ln X1 - 25... (1) ln represents the natural logarithm. Here, X1 [ml / min / mm ２ ]=a[ml] / b[min] / c[mm ２ ] (a: treatment liquid volume [ml], b: treatment time [min], c: filtration area [mm ２ ] y2 [mm] = -5.9 ln X2 - 9.1... (2) ln represents the natural logarithm. Here, X2 [ml / min / mm ２ = a [ml] / b [min] / c [mm ２ (a: amount of treatment liquid [ml], b: treatment time [min], c: filtration area [mm ２ ​

3. The bag filter device according to claim 2, wherein The distance between a plurality of the filter elements installed inside the bag filter is larger than the cake thickness obtained by the formula (1) or the formula (2). A bag filter device characterized by this.

4. The bag filter device according to claim 3, wherein A filter aid supplier for supplying a filter aid is connected to the storage tank, a precoat material supplier for supplying a precoat material is connected to the bag filter, and the bag filter is connected to the sludge recovery container via a gate valve. A bag filter device characterized by this.

5. The bag filter device according to claim 4, wherein a fibrous silicate mineral is used as the filter aid and the precoat material. A bag filter device characterized by this.

6. A storage tank that stores a slurry containing a powdered adsorbent and performs an adsorption treatment for nuclide removal using the powdered adsorbent, and an adsorbent suspension generated by the adsorption treatment in the storage tank is supplied. A concentration device that concentrates the adsorbent suspension by leaching moisture from a cross-flow filter installed inside, a sedimentation separation device that supplies the concentrated water concentrated by the concentration device and separates the concentrated water into supernatant water and sludge, and a bag filter device that filters the sludge sedimentation-separated by the sedimentation separation device. A powder adsorbent recovery system using a bag filter device, characterized in that the bag filter device is a bag filter device according to any one of claims 1 to 5. A powder adsorbent recovery system using a bag filter device characterized by this.

7. A powder adsorbent recovery system using the bag filter device according to claim 6, wherein an aggregating agent supply device that supplies an aggregating agent for performing an aggregating sedimentation treatment and a water quality adjustment reagent supply device that supplies a water quality adjustment reagent are each connected to the sedimentation separation device. A powder adsorbent recovery system using a bag filter device characterized by this.

8. A powder adsorbent recovery system using the bag filter device according to claim 7, wherein a waste liquid transfer pump for transferring the waste liquid containing the sludge is installed in the middle of the pipe connecting the sedimentation separation device and the bag filter device, and the waste liquid transfer pump controls the water flow rate of the waste liquid to the bag filter device by a control device. A powder adsorbent recovery system using a bag filter device characterized by this.

9. A powder adsorbent recovery system using the bag filter device according to claim 6, wherein the powdered adsorbent is any one of sodium titanate, crystalline silicotitanate, supported activated carbon, and iron oxide. A powder adsorbent recovery system using a bag filter device characterized by this.

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