Water sprinkling type purifier and purifying method

Abstract

To efficiently distribute and supply drainage to a treatment tank.SOLUTION: A water sprinkling type purifier 100 for conducting a microorganism reaction treatment to drainage includes a treatment tank 10 loaded with a plurality of microorganism-carrying carriers 11, a sprinkler 20 for sprinkling drainage to the treatment tank 10 from an upper part, and a distribution layer 30 arranged between the treatment tank 10 and the sprinkler 20 for distributing and supplying drainage to the treatment tank 10, wherein the distribution layer 30 includes a resin-made foam 31.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a purification device and a purification method for purifying wastewater by spraying it into a microbial reaction tank. [Background technology]

[0002] The Downflow Hanging Sponge (DHS) method, in which wastewater is sprayed onto a treatment tank filled with a large number of carriers that support microorganisms, and the wastewater is aerobically purified by the decomposition function of the microorganisms held by the carriers, and a purification device (DHS reactor) for carrying out this method have been known for some time. In such purification devices, it is considered ideal to spray wastewater evenly onto the treatment tank in order to efficiently utilize the purification function of the treatment tank.

[0003] The applicant of the present application has proposed a technology for supplying wastewater uniformly throughout the treatment tank even when the flow rate of wastewater supplied to the purification device is reduced (Patent Document 1). In Patent Document 1, for example, a dispersion member (sprinkler plate) is placed between the treatment tank and the sprinkler device at a position where the wastewater dropping from the sprinkler device collides, and the wastewater is dispersed by this dispersion member, thereby dispersing the wastewater widely throughout the treatment tank.

[0004] Furthermore, Patent Document 2 proposes providing a porous layer above the treatment tank in order to widely disperse wastewater sprinkled from a sprinkler device in the treatment tank and to suppress heat radiation within the treatment tank. Patent Document 2 explains that in order to achieve both dispersion of wastewater and suppression of heat radiation, it is particularly preferable to use a porous fleece made of synthetic fiber fabric or glass wool as the porous layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-167194 [Patent Document 2] U.S. Patent No. 4,274,966 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even when sewage is sprayed by colliding with a dispersion member (spray plate) as in Patent Document 1, the sewage drips unevenly in the treatment tank, making it difficult to distribute the sewage evenly throughout the tank. It is known that sewage contains solids, and that solids accumulate on the carriers in the treatment tank as the sewage reacts with the microorganisms held there. However, uneven dripping in the treatment tank can also cause uneven deposition of solids, which can result in uneven flow of sewage (so-called short path). Specifically, if solids contained in the sewage or solids generated by microbial reactions accumulate in one part of the treatment tank, the sewage will flow only through one part of the treatment tank, resulting in insufficient contact between the sewage and the carriers and reduced reaction efficiency.

[0007] To alleviate this uneven distribution of sewage dripping into the treatment tank, a porous layer may be provided above the treatment tank, and sewage may be sprayed onto the porous layer using a sprinkler system, as proposed in Patent Document 2. However, since the porous layer in Patent Document 2 is intended to suppress heat dissipation within the treatment tank, the use of synthetic fiber fabric or glass wool is recommended. Such porous layers made of synthetic fiber fabric or glass wool are prone to localized changes in shape, thickness, density, etc. due to the drip pressure of sewage over long periods of use, and sewage that has penetrated the porous layer is likely to concentrate and flow into areas where the shape has changed. Therefore, if the sewage dripping position is unevenly distributed relative to the porous layer, the flow of sewage from the porous layer to the treatment tank will also be uneven. Furthermore, there are concerns that porous layers made of synthetic fiber fabric may be decomposed by microorganisms held in carriers over long periods of use, may become clogged with solids contained in the sewage, or may become a breeding ground for mold and bacteria due to their poor breathability. Even if a porous layer made of glass wool is used for a long period of time, there are concerns that it may become clogged with solid matter produced by microbial reactions, or that its poor breathability may make it a breeding ground for mold and bacteria. As such, the porous layer proposed in Patent Document 2 requires relatively frequent replacement or cleaning, and is therefore considered to be impractical for use in a purification device.

[0008] Therefore, a main object of the present invention is to propose a technique for more efficiently distributing and supplying wastewater to a treatment tank in a uniform manner. [Means for solving the problem]

[0009] The inventor of the present invention has intensively studied means for solving the problems of the conventional inventions described above, and has discovered that by providing a dispersion layer containing a resin foam between the sprinkler device and the treatment tank, it is possible to uniformly distribute wastewater dripped from the sprinkler device throughout the treatment tank for a relatively long period of time. Based on this discovery, the inventor has come to the conclusion that the problems of the conventional inventions can be solved, and has completed the present invention. Specifically, the present invention has the following configuration or steps.

[0010] A first aspect of the present invention relates to a sprinkler-type purifier 100 for performing microbial reaction treatment on wastewater. The purifier 100 according to the present invention comprises a treatment tank 10, a sprinkler device 20, and a dispersion layer 30. The treatment tank 10 is filled with a plurality of carriers 11 that support microorganisms. The sprinkler device 20 sprinkles wastewater from above the treatment tank 10. The dispersion layer 30 is disposed between the treatment tank 10 and the sprinkler device 20, and supplies the wastewater to the treatment tank 10 in a dispersed manner. The dispersion layer 30 is configured to include a resin foam 31. By providing the dispersion layer 30 containing the resin foam 31 (such as a sponge) on the upper part of the treatment tank 10 in this manner, the dispersion layer 30 temporarily holds the wastewater sprinkled from the sprinkler device 20 by the action of surface tension, while gradually releasing the water. At this time, the wastewater absorbed by the dispersion layer 30 diffuses horizontally within the dispersion layer 30 and is separated from the area where its underside comes into contact with the carrier 11 in the treatment tank 10, making it easier to supply the wastewater uniformly in the horizontal direction of the treatment tank 10. In particular, since the resin foam 31 easily maintains its three-dimensional shape, forming the dispersion layer 30 from such foam 31 makes it less likely to deform due to the pressure of dripping wastewater. Furthermore, since the resin foam 31 is not easily decomposed by the microorganisms held in the carrier 11, it is less likely to deteriorate even with long-term use. This reduces the frequency of replacement of the dispersion layer 30. Therefore, according to the present invention, the dispersion layer 30 can be used for a relatively long period of time.

[0011] In the purification device 100 according to the present invention, the dispersion layer 30 is preferably formed by laying multiple flat foam bodies 31 with gaps between them. Forming the dispersion layer 30 using flat foam bodies 31 in this manner facilitates uniform supply of wastewater to the treatment tank 10. Furthermore, it is anticipated that, over time, microorganisms may invade the foam bodies 31, and solids may form as the microorganisms react with wastewater, accumulating within the foam bodies 31. Furthermore, when solids are accumulated throughout the foam bodies 31, even if wastewater is sprayed from above the foam bodies 31, the wastewater may not penetrate the foam bodies 31 and may slide along the upper surface of the foam bodies 31. In this case, by laying multiple foam bodies 31 with gaps between them, the sliding wastewater flows downward through the gaps and reaches the treatment tank 10. Therefore, wastewater can be guided to the treatment tank 10 with a certain degree of uniformity, even when solids are accumulated within the foam bodies 31.

[0012] In the purification device 100 according to the present invention, the foams 31 forming the dispersion layer 30 are each strip-shaped, polygonal, or circular in plan view (XY plane). Note that the dispersion layer 30 can also be formed using foams 31 of different shapes.

[0013] In the purifying apparatus 100 according to the present invention, the placement position of the foam 31 is preferably adjusted so that the gap is 20 to 50 cm from the position where wastewater drips onto the foam 31. If the distance from the gap is too short, the wastewater dripping onto the foam 31 is likely to separate from the gap, which could result in an uneven supply of wastewater to the treatment tank 10. On the other hand, if the distance from the position where wastewater drips to the gap is too long, there is a concern that the wastewater may not be properly guided to the treatment tank 10 below the foam 31 when solids are filled inside the foam 31, as described above. Therefore, the placement position of the foam 31 is preferably adjusted so that the distance from the position where wastewater drips to the gap (specifically, the shortest distance) is in the range of 20 to 50 cm. Note that it is preferable that the placement position of the foam 31 satisfies the above-mentioned condition for all of the wastewater drip positions, but this is not a limitation. The placement position of the foam 31 may be adjusted so that the above-mentioned condition is satisfied for at least one of the wastewater drip positions. For example, it is preferable that the foam 31 is laid at a position that satisfies the above conditions for more than half of the positions where sewage drips.

[0014] In the purifying device 100 according to the present invention, the foam 31 may have an opening 31a formed therethrough from the top to the bottom. By forming the opening 31a in the foam 31 itself in this way, even when solids have accumulated inside the foam 31 as described above, it becomes possible to guide wastewater to the treatment tank 10 below the foam 31. In this case, the size of the opening 31a (opening area in a plan view) is 25 to 225 mm 2 If the opening 31a is too small, the function of introducing wastewater into the treatment tank 10 through the opening 31a is reduced, whereas if the opening 31a is too large, the function of retaining wastewater in the entire foam 31 is reduced. For this reason, the size of each opening 31a is set to 25 to 225 mm. 2 It is appropriate to set the range as follows.

[0015] In the purifying device 100 according to the present invention, the foam 31 preferably has an average number of cells per square inch of 20 to 50. A cell refers to each unit of cavity formed in the foam 31. The foam 31 is obtained, for example, by mixing a base material with a foaming agent and foaming the mixture. During this process, gas (air bubbles) generated in the base material form cells (cavities) within the foam 31. If the number of cells per unit volume in the foam 31 is small, the amount of wastewater held increases and clogging is less likely to occur, making it easier to uniformly supply wastewater to the treatment tank 10. On the other hand, if the number of cells per unit volume is large, the amount of wastewater held decreases and clogging is more likely to occur, making it harder to uniformly supply wastewater to the treatment tank 10. For this reason, it is preferable to use a foam 31 with an average number of cells per square inch of 20 to 50.

[0016] In the purification device 100 according to the present invention, the foam 31 preferably has an average cell diameter of 0.5 to 1.25 mm. By using foam 31 with an average cell diameter within the above range, it becomes easier to supply wastewater to the treatment tank 10 uniformly.

[0017] In the purification device 100 according to the present invention, the foam 31 preferably has a porosity (volume %) of 90% or more. By using a foam 31 with a porosity in the above range, it becomes easier to supply wastewater uniformly to the treatment tank 10.

[0018] In the purification device 100 according to the present invention, the foam 31 is preferably flat and has a thickness of 15 to 50 mm. By using a foam 31 having a thickness within the above range, it becomes easier to supply wastewater to the treatment tank 10 uniformly.

[0019] In the purification device 100 according to the present invention, the foam 31 may have a profiled lower surface. The profiled lower surface is formed by forming corrugated projections and depressions on the surface of the foam 31.

[0020] In the purifying device 100 according to the present invention, the foam 31 has an average number of membrane cells of 1 cm 3It is preferable that there are 5 or less per unit area.

[0021] A second aspect of the present invention relates to a sprinkler-type purification method for subjecting wastewater to a microbial reaction treatment. In the purification method according to the present invention, wastewater is sprinkled from a sprinkler device 20 onto a dispersion layer 30 (sprinkler step). The dispersion layer 30 then disperses and supplies the wastewater to a treatment tank 10 (dispersion step). In the treatment tank 10, the carriers 11 holding microorganisms perform a microbial reaction treatment on the wastewater (treatment step). In the present invention, the dispersion layer 30 is configured to include a resin foam 31. [Effects of the Invention]

[0022] According to the present invention, wastewater can be efficiently dispersed and supplied to the treatment tank. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram showing a purification device according to one embodiment of the present invention. [Figure 2] FIG. 2 shows a first example of a foam constituting the dispersion layer. [Figure 3] FIG. 3 shows a second example of a foam constituting the dispersion layer. [Figure 4] FIG. 4 shows another example of a foam constituting the dispersion layer. [Figure 5] FIG. 5 shows an example of an apertured foam. [Figure 6] Figure 6 shows an example of a profiled foam. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and includes appropriate modifications of the embodiments described below within the scope obvious to those skilled in the art. In the present specification, "A to B" means "A or more and B or less." The drawings are also provided with three-dimensional coordinate axes of XYZ, where the X axis indicates the horizontal direction of the purification device 100, the Y axis indicates the depth direction of the purification device 100, and the X axis indicates the height direction of the purification device 100.

[0025] FIG. 1 shows a purifier 100 according to one embodiment of the present invention. The purifier 100 of this embodiment is used, for example, as part of an organic wastewater treatment system. The purifier 100 purifies wastewater that has been anaerobically treated, for example, by an up-flow anaerobic sludge blanket (UASB) reactor, through aerobic biological treatment. Specifically, the purifier 100 sprinkles wastewater supplied from a wastewater supply pipe onto microorganism-retaining carriers filled in a treatment tank, and aerobically purifies the wastewater using the decomposition function of the microorganisms retained by the carriers. As shown in FIG. 1, the purifier 100 includes a treatment tank 10, a sprinkler device 20, a dispersion layer 30, and a water collection section 40.

[0026] The treatment tank 10 is a tank filled with a large number of carriers 11 that retain microorganisms, and wastewater is purified in this tank. The material and shape of the carrier 11 are not particularly limited, and known carriers can be used. The carrier 11 is preferably porous and water-retentive in order to increase the microbial retention density and ensure hydraulic retention time. For example, the carrier 11 may be made of a resin foam such as polyurethane. The shape of the carrier 11 may be a cylindrical, cylindrical, square prism, square tubular, or other polygonal prism or tubular shape. Examples of the microorganisms retained in the carrier 11 include heterotrophic bacteria that aerobically oxidize dissolved substances and autotrophic bacteria that aerobically oxidize ammonia, sulfur-based odors (hydrogen sulfide, methyl sulfide, etc.), and methane.

[0027] The treatment tank 10 is placed on a stand (not shown). The treatment tank 10 has a bottom plate 12 at the lower end of the internal space filled with the carrier 11, and this bottom plate 12 has a plurality of liquid passage holes 12a formed in it. The wastewater that has passed through the carrier 11 of the treatment tank 10 is introduced into the water collection section 40 provided below it through the liquid passage holes 12a in the bottom plate 12.

[0028] The sprinkler device 20 is disposed above the treatment tank 10 and sprinkles wastewater onto the treatment tank 10. A known sprinkler device can be used as the sprinkler device 20, but for example, the device disclosed in Patent Document 1 (JP 2018-167194 A) is preferably used. Specifically, the sprinkler device 20 receives wastewater from an outlet hole in a wastewater supply pipe 21 (header pipe) and sprinkles the wastewater. The sprinkler device 20 includes a receiving member 22, a drain pipe 23, a branch pipe 24, and a nozzle 25. While the drain pipe 23, the branch pipe 24, and the nozzle 25 are depicted as separate components in FIG. 1, they may also be configured as a single component. The receiving member 22 is a gutter-shaped component with an open top. The receiving member 22 receives wastewater flowing down from the outlet hole in the wastewater supply pipe 21 and supplies the wastewater to the drain pipe 23 through an insertion hole formed in the bottom surface. The drain pipe 23 is fixed to the receiving member 22 while being inserted through an insertion hole on the underside of the receiving member 22. The branch pipe 24 is connected to the lower end of the drain pipe 23 and is configured to branch the wastewater flowing through the drain pipe 23 toward multiple outlets and slope downward. In the example shown in FIG. 1, the sprinkler device 20 has two outlets, but this is not limited to this, and the number of outlets can be three, four, or more. The nozzles 25 are attached to the ends of the branch pipes 24 to change the flow of wastewater discharged from the outlets. By adjusting the direction and inclination of the nozzles 25, it is possible to adjust the discharge direction of the wastewater, specifically the drip position of the wastewater.

[0029] The dispersion layer 30 is disposed between the treatment tank 10 and the sprinkler device 20. The dispersion layer 30 receives and temporarily retains wastewater discharged from the sprinkler device 20, dispersing the wastewater over a wide area centered on the drip position and supplying it to the treatment tank 10. The dispersion layer 30 is composed of a foam 31. The foam 31 has a porous structure with countless micropores formed therein. A network of fine tubes surrounding the micropores absorbs liquid by capillary action and retains the liquid within the micropores. Therefore, when wastewater is dripped from above the foam 31, the wastewater is dispersed three-dimensionally within the foam 31 centered on the drip position. Furthermore, as wastewater continues to drip onto the foam 31, the wastewater already retained within the foam 31 is pushed down by the newly entering wastewater, and is eventually released from the bottom surface of the foam 31. In particular, when the carrier 11 in the treatment tank 10 is in contact with the underside of the foam 31, the carrier 11 in contact therewith absorbs the wastewater in the foam 31. By utilizing this phenomenon, the dispersion layer 30 disperses the wastewater received from the sprinkler device 20 over a wide range and uniformly over the carrier 11 in the treatment tank 10.

[0030] In the present invention, the foam 31 is made of resin. The resin foam 31 is obtained by a chemical foaming method, which mainly involves mixing a foaming agent with a base material and foaming the base material by generating gas through decomposition of the foaming agent. Examples of resins used as the base material include polyurethane (PUR)-based resins, polyethylene (PE)-based resins, polypropylene (PP)-based resins, polystyrene (PS)-based resins, and polyvinyl chloride (PVC)-based resins. The base material may be made of one of these resins or a mixture of two or more of them. Among these, it is preferable to use a polyurethane-based resin as the foam 31. Examples of polyurethane-based resins include polyether-based polyurethane resins, polyester-based polyurethane resins, polycarbonate-based polyurethane resins, silicone-based polyurethane resins, acrylic-based polyurethane resins, and modified polyurethane resins. In particular, it is preferable to use a polyether-based polyurethane resin. The polyether polyurethane resin foam 31 has high durability and shock absorption properties, so its shape is not easily deformed even when sewage is continuously dripped onto it for a long period of time, and the sewage that falls onto its surface is not easily scattered, so the sewage can be stably dispersed. Furthermore, the molecular structure of polyether polyurethane resin is relatively stable, so it is resistant to sewage and microorganisms.

[0031] The water collection section 40 collects the liquid that has passed through the treatment tank 10 and discharges it to the outside. As mentioned above, the bottom plate 12 with the liquid passage holes 12a is provided at the lower end of the treatment tank 10, and the liquid that has passed through these liquid passage holes 12a flows into the water collection section 40. The bottom surface of the water collection section 40 is cone-shaped, and a drain pipe 41 is provided at the lowest part of the bottom surface. Therefore, the liquid collected in the water collection section 40 is discharged to the outside through this drain pipe 41.

[0032] Next, the dispersion layer 30 and the foam 31 that forms it will be described in more detail. As described above, the dispersion layer 30 disperses the wastewater from the sprinkler device 20 and supplies it to the treatment tank 10. In order to efficiently disperse and supply the wastewater in this way, it is preferable to use a foam 31 that has appropriate water retention and shape stability.

[0033] Specifically, the foam 31 is obtained by foaming a resin substrate with a foaming agent, as described above. The foam 31 thus obtained has numerous fine cells (cavities) formed therein. The average number of cells per inch of length inside the foam 31 is preferably 20 to 50, and more preferably 20 to 40 or 30 to 40. To measure the average cell number, the foam 31 is sliced ​​to obtain a specimen, and an image of the cross section of the specimen is captured using a digital microscope (e.g., product name "VHX-600" manufactured by Keyence Corporation). The number of cells per square inch is counted from this image. The same process is performed on other specimens to determine the average number of cells per square inch (also known as cell density). Ten specimens are measured.

[0034] Furthermore, cells with thin membranes may exist in the foam 31. Since these membranes can be a factor that hinders the flow of wastewater, it is advisable to select a foam 31 with a small number of cells with membranes. Specifically, the foam 31 should have an average number of cells with membranes of 1 cm. 3 It is preferable that there are no more than 5 pieces per 1cm, and 3 pieces per 1cm 3 To measure the number of cells with membranes, the foam 31 is cut to 1 cm 3 The sample is cut into a cube of 1 cm, and each of the six sides of the sample is visually inspected to count the number of cells with membranes. The same procedure is repeated for other samples, and the number of cells with membranes is counted. 3 The average number of cells with membranes per cell is calculated. Ten samples are measured. In the case of resin foam (sponge, etc.), even if the shape of the foam is deformed, it is easy for it to return to its original shape due to the cushioning effect of the membrane structure, and it is possible to suppress the cause of clogging while maintaining good water retention. However, synthetic fiber fabrics and glass wool do not have the membrane structure of resin foam, so they are easily crushed, which reduces water retention and can easily cause clogging.

[0035] The average cell diameter of foam 31 is preferably 0.5 to 1.25 mm, and particularly preferably 0.5 to 1.2 mm or 0.6 to 1.0 mm. The average cell diameter, like the average cell number, can be determined by capturing an image of a specimen obtained by slicing foam 31 with a digital microscope and analyzing the image. Specifically, the average cell diameter can be determined by capturing an enlarged image of the cross section of the foam with a digital microscope, measuring the area of ​​all cells appearing in a certain area (100 × 100 mm) of the cut surface, converting the area to a circle-equivalent diameter, and averaging it by the number of cells.

[0036] The porosity (volume %) of foam 31 is preferably 90% or more or 93% or more, and particularly preferably 90 to 99.9% or 93 to 98%. The porosity of the foam, like the average cell number, can be determined by slicing foam 31, capturing an image of a specimen using a digital microscope, and analyzing the image. Specifically, the image of the specimen of foam 31 is binarized, and the area ratio of the matrix phase consisting of resin to the bubble phase consisting of air bubbles can be regarded as the porosity (the volume fraction of raw material in the foam after expansion molding).

[0037] FIG. 2 shows an example in which a dispersion layer 30 is formed by arranging a plurality of foams 31 side by side. In the example shown in FIG. 2, a plurality of strip-shaped foams 31 extending elongately in the depth direction (Y direction) are arranged side by side in the horizontal direction (X direction). In FIG. 2, three foams 31 are arranged side by side in the horizontal direction, but the number of foams 31 is not limited to this and can be adjusted to four, five or more foams according to the width of the treatment tank 10. The length of each foam 31 in the depth direction can also be adjusted according to the depth of the treatment tank 10.

[0038] It is also preferable that foam 31 be laid almost horizontally above treatment tank 10. If foam 31 is laid at an angle above treatment tank 10, the wastewater held in foam 31 will flow downward, making it difficult to uniformly supply wastewater from foam 31 to treatment tank 10. For this reason, it is preferable that foam 31 be laid almost horizontally.

[0039] 2, foam 31 has a constant thickness T and is formed into a flat rectangular shape in a plan view. The thickness T of foam 31 is preferably 15 to 50 mm, and particularly preferably 20 to 50 mm or 30 to 45 mm. In this way, by adjusting the thickness T of foam 31 as well as the cell diameter and cell density, the water retention capacity of foam 31 can be adjusted to an appropriate value.

[0040] Furthermore, it is preferable that the change in thickness T of foam 31 be small between the state before absorbing water (dry state) and the state after absorbing water (wet state). Because resin foam 31 has a porous structure, when it absorbs water, the air inside foam 31 is replaced with water, increasing its volume and resulting in a tendency for thickness T to increase. When the thickness T of foam 31 in a dry state is taken as 100%, the thickness T of foam 31 in a wet state is preferably 103% or less. Specifically, the thickness in a wet state is preferably 100 to 103% of the thickness in a dry state, and particularly preferably 100 to 102% or 100 to 101%. The measurement method involves cutting two specimens of the same dimensions and thickness (e.g., 20 x 20 x 20 mm) from the foam 31. One specimen is left to dry naturally at room temperature (25°C), humidity (50%), and atmospheric pressure (1 atm) for six hours, then placed on a flat surface to form a dry specimen. The other specimen is immersed in water, slowly lifted, and allowed to cool until the water stops dripping. Then, it is placed on a flat surface to form a wet specimen. The thicknesses of the dry and wet specimens are then measured and compared. Foam 31, which is resistant to deformation even when absorbing water, does not change significantly in thickness due to water absorption, resulting in high shape stability and making it easier for the product to maintain its shape. Furthermore, minimal thickness change due to water absorption stabilizes the cushioning and heat-retaining properties of foam 31.

[0041] 2, when a plurality of foam bodies 31 are arranged side by side, it is preferable to form a gap S between each foam body 31. The gap S is preferably 1 mm to 100 mm, and particularly preferably 3 to 80 mm or 5 to 50 mm.

[0042] Furthermore, when arranging foam bodies 31 on the carriers 11 filled in the treatment tank 10, it is advisable to place the foam bodies 31 below the drip position of the wastewater discharged from the sprinkler system 20. In Fig. 2, the drip position of the wastewater dripping onto the foam bodies 31 is indicated by the symbol D. In this case, the shortest distance L from the drip position D of the wastewater on one foam body 31 to the gap S between another adjacent foam body 31 is preferably 10 to 50 cm, and particularly preferably 10 to 45 cm or 10 to 15 cm.

[0043] The width W of the foam 31 may be designed in consideration of the shortest distance L from the dripping position D to the gap S. For example, the width W of the foam 31 is preferably 20 to 100 cm, and particularly preferably 20 to 90 cm or 20 to 30 cm.

[0044] Next, FIG. 3 shows another example of the foam 31. In the example shown in FIG. 3, each foam 31 is molded into a quadrangular shape, specifically a square shape, in a plan view. A plurality of such quadrangular foams 31 are arranged in the horizontal direction (X direction) and the depth direction (Y direction), forming a dispersion layer 30. In particular, in the example shown in FIG. 3, a row of foams 31 arranged in the depth direction and an adjacent row of foams 31 are offset so that the centers of the foams 31 are not aligned in a straight line in the horizontal direction. Specifically, in the example shown in FIG. 3, the positions of the foams 31 in a row of foams 31 and the adjacent row of foams 31 are shifted by half a foam in the depth direction. In this way, the quadrangular foams 31 can also be arranged in a so-called staggered pattern.

[0045] 3, the foams 31 are arranged with not only a gap S1 in the horizontal direction (X direction) but also a gap S2 in the depth direction (Y direction). As described above, the horizontal gap S1 is preferably 1 mm to 100 mm, and more preferably 3 to 80 mm or 5 to 50 mm. The same is true for the vertical gap S2, which is preferably 1 mm to 100 mm, and more preferably 3 to 80 mm or 5 to 50 mm.

[0046] Furthermore, in the example shown in Figure 3, the shortest distance L from the sewage drip position D on a foam 31 to the gap S1, S2 between another adjacent foam 31 is preferably 10 to 50 cm, and particularly preferably 10 to 45 cm or 10 to 15 cm.

[0047] 3, the shape of the foam 31 in plan view is a square, but this is not limited thereto, and the shape of the foam 31 may be rectangular and multiple foams may be arranged in the horizontal direction (X direction) and the depth direction (Y direction). Also, in the example shown in Fig. 3, the foams 31 are arranged in a so-called staggered pattern, but this is not limited thereto, and the foams 31 may be arranged so that their centers (the centers in the X direction and the Y direction if they are square or rectangular) are aligned on a straight line in the horizontal direction and the depth direction.

[0048] Next, Fig. 4 shows another example of the foam 31. In the example of Fig. 4(a), circular foams 31 are arranged side by side with a gap S therebetween in a plan view. Since the foams 31 have a predetermined thickness, they are actually cylindrical. In this way, it is also possible to form a dispersion layer 30 by arranging a plurality of cylindrical foams 31. In this case, it is preferable to arrange the wastewater so that it drips near the center of the circular upper surface of the foam 31.

[0049] In the example of FIG. 4(b), hexagonal foams 31 are arranged side by side with gaps S between them in a plan view. Since the foams 31 have a predetermined thickness, they are actually hexagonal pillar-shaped. In this way, it is possible to form the dispersion layer 30 by arranging a plurality of hexagonal pillar-shaped foams 31. In this case, it is preferable that the wastewater drips near the center of the hexagonal upper surface of the foam 31. Furthermore, when the foams 31 are hexagonal pillar-shaped, it is also possible to make the gaps S between the foams 31 all the same width. By forming the dispersion layer 30 by evenly arranging the hexagonal pillar-shaped foams 31 in this way, it is possible to more uniformly disperse wastewater.

[0050] FIG. 5 shows an example of a foam 31 having an opening 31a formed therein. The opening 31a is a hole that penetrates the foam 31 from the top surface to the bottom surface. The opening 31a can be formed, for example, by punching the foam 31. The opening 31a can be formed at any appropriate position in the foam 31, but it is preferable to form it at a predetermined distance from the sewage drip position D. In other words, it is undesirable for the sewage drip position D and the opening 31a to overlap. For example, the shortest distance L from the drip position D to the opening 31a is preferably 10 to 50 cm, and particularly preferably 10 to 45 cm or 10 to 15 cm.

[0051] The shape of the opening 31a is not particularly limited, and may be, for example, a square shape in a plan view as shown in Fig. 5. Although not shown, the opening 31a may be a circle or another polygonal shape.

[0052] The size of the opening 31a (area in a plan view) is 25 to 225 mm 2 It is preferable that the size of opening 31a is in the range of 1 mm. For example, if opening 31a is rectangular as in the example shown in Figure 5, its size can be calculated from the horizontal length x and the depth y. For example, if opening 31a is square, the length of one side will be 5 to 15 mm. The volume of opening 31a is calculated by multiplying the area of ​​opening 31a by the thickness T of foam 31.

[0053] The area of ​​the openings 31a formed in the foam 31 per square meter is 0.01125 to 0.0225 m 2 If the number of openings 31a formed in the foam 31 is too large, the foam 31 will not be able to exhibit adequate water retention, whereas if the number of openings 31a is too small, the effect of dispersing wastewater using the openings 31a will be impaired. For this reason, it is preferable that the area of ​​the openings 31a per square meter be within the above-mentioned range.

[0054] 6 shows an example of a foam 31 that has been profiled. By the profile processing, convex portions 31b and concave portions 31c are repeatedly and continuously formed on the surface of the foam 31 in the lateral direction (X direction) and the depth direction (Y direction). The profile processing may be performed on only one of the upper surface side (sprinkler device 20 side) and the lower surface side (treatment tank 10 side) of the foam 31, or on both sides.

[0055] In particular, when the underside of the foam 31 is profiled, the convex portions 31b on the underside of the foam 31 directly contact the carrier 11 in the treatment tank 10. Because the carriers 11 located at the top of the treatment tank 10 vary in height, it is usually difficult to keep the entire foam 31 horizontal. However, by forming multiple convex portions 31b on the underside of the foam 31 that contacts the carrier 11, the convex portions 31b are only deformed at the contact points with the carrier 11, and the foam 31 as a whole is supported while remaining horizontal. If the entire foam 31 is kept horizontal, the flow of wastewater within the foam 31 is less likely to become uneven, thereby enhancing the effectiveness of the foam 31 in uniformly dispersing wastewater. Furthermore, if multiple convex portions 31b are formed on the underside of the foam 31, the wastewater absorbed within the foam 31 collects on these convex portions 31b. The wastewater within the foam 31 then flows down the convex portions 31b on the underside and is supplied to the carrier 11 in contact with it. Therefore, by forming convex portions 31b on the underside of the foam 31, the wastewater is transmitted from the numerous convex portions spread across the horizontal surface, improving the dispersion of the wastewater supplied from the foam 31 to the carrier 11.

[0056] Furthermore, as shown in the cross section of Figure 6, when profiling foam 31, it is preferable to add protrusions 31b of height H to the base portion of foam 31 while maintaining the base portion of thickness T. As described above, the thickness T of the base portion is preferably 15 to 50 mm. The height H of protrusions 31b is preferably in the range of 50 to 100% of the thickness T of the base portion, and may be 60 to 100% or 70 to 100%. Specifically, the height H of protrusions 31b is preferably 7 to 50 mm, and particularly preferably 10 to 50 mm or 15 to 45 mm.

[0057] In the above description of the present invention, the embodiments of the present invention have been described with reference to the drawings in order to express the contents of the present invention. However, the present invention is not limited to the above embodiments, and includes modifications and improvements that are obvious to those skilled in the art based on the matters described in the present specification. [Explanation of symbols]

[0058] 10... Treatment tank 11... Carrier 12...Bottom plate 12a...Liquid hole 20...Sprinkler system 21...Sewage supply pipe 22... Receiving member 23... Drain pipe 24...Branch pipe 25...Nozzle 30...Dispersion layer 31...Foam 31a...opening 31b...projection 31c...recess 40...water collecting section 41...Drainage pipe 100...Purification device

Claims

1. A sprinkler-type purification device for performing microbial reaction treatment on wastewater, a treatment tank filled with a plurality of carriers holding microorganisms; a sprinkler device that sprinkles wastewater from above the treatment tank; a dispersion layer disposed between the treatment tank and the sprinkler device, which disperses and supplies the wastewater to the treatment tank; The dispersion layer includes a resin foam. Purification equipment.

2. The dispersion layer is made of a plurality of flat foam bodies laid with gaps between them. The purification device of claim 1 .

3. Each of the foams has a strip-like, polygonal, or circular shape in plan view. The purification device according to claim 2 .

4. The position where the foam is laid is adjusted so that the gap is 20 to 50 cm away from the dripping position of the wastewater onto the foam. The purification device according to claim 2 .

5. The foam has an opening formed therethrough from the top surface to the bottom surface. The purification device according to claim 1 or 2.

6. The size of the opening is 25 to 225 mm ２ is The purification device according to claim 5.

7. The foam has an average number of cells per inch of 20 to 50. The purification device according to claim 1 or 2.

8. The foam has an average cell diameter of 0.5 to 1.25 mm. The purification device according to claim 1 or 2.

9. The foam has a porosity of 90% or more. The purification device according to claim 1 or 2.

10. The foam is flat and has a thickness of 15 to 50 mm. The purification device according to claim 1 or 2.

11. The foam has a profiled underside. The purification device according to claim 1 or 2.

12. The foam has an average number of membrane cells of 1 cm ３ There are five or fewer per The purification device according to claim 1 or 2.

13. A sprinkling type purification method that performs microbial reaction treatment on wastewater, a step of spraying wastewater onto the dispersion layer from a spraying device; a step of dispersing and supplying wastewater to a treatment tank by the dispersion layer; a step of subjecting the wastewater to a microbial reaction treatment in the treatment tank using a carrier holding microorganisms, The dispersion layer includes a resin foam. Purification method.

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