Wastewater treatment device and wastewater treatment method

Abstract

To prevent clogging between membranes from occurring, which is caused by the accumulation of solid matters present in wastewater, by letting wastewater (fluid) smoothly flow between adjacent gas supply bodies, in an aerobic microorganism wastewater treatment device using gas supply bodies.SOLUTION: A wastewater treatment device (50) comprises a plurality of supply body units (52), the plurality of supply body units (52) each comprise a waterproof and gas-permeable gas supply body (10), and the gas supply bodies (10) each form a compartmental space separated from the wastewater, between the membrane faces. A gas, a fluid derived from the wastewater, or a solid matter is disposed between a pair of adjacent membrane faces of a pair of adjacent gas supply bodies (10), or between a pair of adjacent membrane faces in contact with the wastewater, of a gas supply body (10).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This relates to a wastewater treatment system that utilizes the action of aerobic microorganisms to decompose organic matter in the water and purify the wastewater. [Background technology]

[0002] Aerobic microbial wastewater treatment equipment is widely used as a method for treating organic wastewater. However, aeration using an aeration tube has low oxygen dissolution efficiency and requires aeration at a pressure higher than the water pressure applied to the aeration tube, resulting in high power costs for the blower.

[0003] A membrane aerated biofilm reactor (MABR)-type wastewater treatment device is being considered, which treats wastewater by attaching microorganisms to a gas supplying body that is permeable to gas but not to liquid. This device can reduce the pressure applied to the air supply, making it possible to reduce electricity costs. Examples of such gas supplying bodies are disclosed in Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5997052 [Patent Document 2] JP 2021-133342 A Summary of the Invention [Problem to be solved by the invention]

[0005] In an aerobic microbial wastewater treatment device using a gas supply, it is important to stably attach microorganisms to the gas supply in order to realize wastewater treatment performance. In the case of Prior Art 1, a spacer net is provided to maintain the gap between adjacent membranes. Although this spacer net is effective in maintaining the gap between the membranes, it impedes the flow of fluid, causing solids in the wastewater to accumulate and cause inter-membrane blockage.

[0006] In the case of Patent Document 2, a housing member is provided to seal the ends of the hollow fiber membranes. This housing impedes the flow of fluid, and solid matter in the wastewater accumulates, causing inter-membrane blockage. The present invention provides a wastewater treatment device that solves these problems and prevents membrane clogging. [Means for solving the problem]

[0007] The wastewater treatment device according to a first aspect is a wastewater treatment device that purifies wastewater by utilizing the action of microorganisms in the wastewater, The wastewater treatment device includes a feeder unit, The supply unit has a waterproof, gas-permeable gas supply unit, The gas supply defines a compartment space separated from the wastewater, A gas or wastewater-derived fluid or solid is disposed between two adjacent membrane surfaces of two adjacent gas suppliers, or between two membrane surfaces of one gas supplier that contacts the wastewater. Here, the membrane surface of the gas supplier refers to the surface of the gas supplier that contacts the wastewater.

[0008] In the wastewater treatment device of the first aspect, a gas or wastewater-derived fluid or solid is placed between two membrane surfaces that contact the wastewater from the gas supplier, and since there are no obstacles other than the wastewater, the flow of the wastewater is not impeded and good wastewater treatment can be achieved.

[0009] A wastewater treatment device according to a second aspect is the wastewater treatment device according to the first aspect, further comprising an air diffuser, the air diffuser being installed below the gas supplier.

[0010] A wastewater treatment device according to a third aspect is the wastewater treatment device according to the first or second aspect, wherein the gas supply body has a folded structure folded back in a horizontal direction, and a membrane surface of the gas supply body extends in a vertical direction.

[0011] A wastewater treatment device according to a fourth aspect is the wastewater treatment device according to the first or second aspect, wherein the gas supplier has a folded structure folded back in the horizontal direction, and the distance between adjacent membrane surfaces is 5 mm or more and 200 mm or less.

[0012] A wastewater treatment device according to a fifth aspect is the wastewater treatment device according to the fourth aspect, wherein the length from one folded portion to the next folded portion is defined as a folding unit, and the folding unit length is 100 mm or more and 3000 mm or less.

[0013] A sixth aspect of the present invention relates to a wastewater treatment device according to the third aspect, wherein the angle formed by the return is 90 degrees or less and 180 degrees or less.

[0014] A seventh aspect of the present invention is the wastewater treatment device according to the first or second aspect, wherein the gas supplier has a vertical distance of 2500 mm or less.

[0015] The wastewater treatment device according to an eighth aspect is the wastewater treatment device according to the first or second aspect, wherein a total horizontal path of the vertical end points of the fractionation space in the gas supplier is 500 m or less.

[0016] A wastewater treatment device according to a ninth aspect is the wastewater treatment device according to the first or second aspect, The gas supply bodies are installed in multiple stages, one above the other.

[0017] A wastewater treatment method according to a tenth aspect is a wastewater treatment method in which a gas supplier is disposed in a treatment tank and the wastewater is purified by utilizing the action of microorganisms in the wastewater, The gas supplier forms a space separated from the wastewater by a waterproof and air-permeable membrane, The gas supply body has at least one repeated structure of mountain folds and valley folds when viewed from above, The treatment tank has at least one wastewater inlet and at least one wastewater outlet; Wastewater treatment occurs from the inlet to the outlet. Effect of the Invention

[0018] In the wastewater treatment device disclosed herein, a gas or wastewater-derived fluid or solid is placed between two membrane surfaces that come into contact with the wastewater from the gas supplier, and since there are no obstacles, the flow of wastewater is not impeded, allowing for good wastewater treatment. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a side view of a wastewater treatment system 100. [Figure 2A] FIG. 2 is a side view of the wastewater treatment device 50. [Figure 2B] FIG. 2 is a top view of the wastewater treatment device 50. [Diagram 3] FIG. 2 is a side view of the wastewater treatment device 50 (particularly a view for explaining a method for fixing the supplier unit 52 to a fixing bracket 63). [Figure 4] FIG. 2 is a side view of the wastewater treatment device 50 (particularly for explaining the flow of fluid in the wastewater caused by the air discharged by the air diffuser 70). [Diagram 5] FIG. 2 is a side view illustrating the arrangement in a treatment tank 51 of the wastewater treatment device 50. [Figure 6] FIG. 2 is a top view illustrating the arrangement in a treatment tank 51 of the wastewater treatment device 50. [Figure 7] FIG. 2 is a diagram illustrating an air diffuser 71. [Figure 8A] 10 is a diagram for explaining one embodiment of an air diffusing pipe 71. FIG. [Figure 8B] 11 is a diagram illustrating another embodiment of the air diffusing pipe 71. FIG. [Figure 8C] 11 is a diagram illustrating another embodiment of the air diffusing pipe 71. FIG. [Figure 8D] 11 is a diagram illustrating another embodiment of the air diffusing pipe 71. FIG. [Figure 9A] 1 is a diagram showing the connection of the gas supplier 10 to the gas supply manifold 35 and the exhaust manifold 45. FIG. [Figure 9B] 2 is a cross-sectional view and a partially enlarged cross-sectional view of a gas supply body 10. FIG. [Figure 10] FIG. 2 is a perspective view of gas delivery layer 12. [Figure 11]FIG. 2 is a top view of a supply unit 52 (gas supply 10 is flat). [Figure 12] FIG. 13 is a top view of another supplier unit 52 (gas supplier 10 has a folded-back structure). [Figure 13] FIG. 13 is a top view of another supplier unit 52 (gas supplier 10 has a folded-back structure). [Figure 14] FIG. 13 is a top view of another supply unit 52 (gas supply 10 having a spiral shape). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] First Embodiment (Wastewater treatment system 100) The wastewater treatment system 100 of this embodiment utilizes the action of microorganisms contained in the wastewater to decompose at least one organic matter or nitrogen source in the wastewater, thereby purifying the wastewater. As shown in FIG. 1, the wastewater treatment system 100 includes a wastewater treatment tank 51 and a wastewater treatment device 50.

[0021] (Wastewater treatment tank 51) As shown in Figs. 1, 2A, and 2B, the wastewater treatment tank 51 is a bottomed container in which wastewater W is stored. As shown in Fig. 2B, the wastewater treatment tank 51 has a rectangular shape when viewed from above. The wastewater treatment tank 51 has four side walls 511-514 and a bottom surface 515. An inlet 51a for the wastewater W is arranged on the side wall 511, and an inlet 511a and an outlet 51b for the wastewater W are arranged on a side wall 512 opposite to the side wall 511. The inlet 51a and the outlet 51b may be provided inversely. There may be one inlet 51a or a plurality of inlets. There may be one outlet 51b or a plurality of outlets.

[0022] In this embodiment, the inlet 51a and the outlet 51b are always open. The wastewater W is continuously or intermittently supplied from the inlet 51a to the outlet 51b disposed opposite the inlet 51a.

[0023] The volume of the wastewater treatment tank is not particularly limited, but may be, for example, 1 m 3 More than 10,000m 3 The following volume is sufficient:

[0024] (Wastewater treatment device 50) The wastewater treatment device 50 includes a supplier unit 52, an air sending section 30, an exhaust section 40, and an air diffuser .

[0025] (Supplier Unit 52) As shown in FIG. 3, the supplier unit 52 is a unitized gas supplier 10, and is disposed inside the wastewater treatment tank 51. In FIG. 1, the supplier unit 52 is configured by a plurality of gas suppliers 10 arranged in parallel. The supplier unit 52 may further include a support 61 that supports the gas supplier 10. The gas supplier unit 52 may have a rectangular parallelepiped shape or a cylindrical shape as a whole. When the gas supplier unit 52 has a rectangular parallelepiped shape, the support 61 may be disposed on the side of the rectangular parallelepiped part. The support 61 may be a pipe. The support 61 may be made of metal. The supplier unit 52 is disposed so that each gas supplier 10 is entirely immersed in the wastewater W during use. That is, it is disposed below the water surface.

[0026] Moreover, installing the gas supply bodies 10 one by one in the wastewater treatment tank 51 takes time and increases installation costs. Therefore, a supply body unit 52 that holds a plurality of gas supply bodies 10 in parallel may be manufactured, and one or more of the supply body units 52 may be installed inside the wastewater treatment tank 51. In this way, many gas supply bodies 10 can be installed in the wastewater treatment tank 51 in a short time, so that the construction time and installation costs can be significantly reduced. Also, the supply body units 52 may be installed in multiple stages depending on the height of the tank. In this way, the filling rate of the gas supply body in the tank can be increased, and the treatment efficiency per tank volume can be improved. Hereinafter, a method for fixing the supply body unit will be described with reference to FIG. 3.

[0027] Since the supplier unit 52 has a plurality of hollow gas suppliers 10, when the supplier unit 52 is installed in the wastewater treatment tank 51, buoyancy may act on the supplier unit 52. In addition, the supplier unit 52 may be subjected to rocking motion due to convection of the wastewater in the tank. To prevent this, a fixing bracket 63 and a floating prevention member 62 are used to prevent the supplier unit 52 from floating up or falling over.

[0028] The fixing bracket 63 fixes the supplier unit 52 in the wastewater treatment tank 51. The fixing bracket 63 is an L-shaped steel material. The fixing bracket 63 is fixed to the bottom surface 515 of the wastewater treatment tank 51 and has a structure extending vertically. The fixing bracket 63 fixes, for example, four corners of the supplier unit 52 to the bottom surface 515 of the wastewater treatment tank 51. This fixes the supplier unit 52 without swinging left and right. The number of fixing brackets 63 is not limited to four, and any number may be used as long as the supplier unit 52 is fixed. The fixing bracket 63 may be an H-shaped shape or a cylindrical shape with a groove other than an L-shaped shape. It is sufficient that the fixing bracket 63 is capable of fixing the supplier unit 52 to the wastewater treatment tank 51.

[0029] The anti-floating member 62 fixes the supplier unit 52 to the side walls 511-514 of the wastewater treatment tank 51. The anti-floating member 62 has an L-shaped structure and includes a base plate and a vertical plate extending vertically from the base plate. The base plate is fixed to the upper part of the side wall of the wastewater treatment tank 51. The vertical plate holds down the supplier unit 52 from above, thereby preventing the supplier unit 52 from floating up.

[0030] The air diffuser 70 and the supply unit 52 may each be provided with a fixing bracket connection part 63a, 63b that matches the shape of the fixing bracket 63. In addition, the height of the fixing bracket 63 in the vertical direction of the tank may be equal to or greater than the height of the fixing bracket connection part 63a of the air diffuser 70 and the supply unit 52 that is located at the highest position from the water surface. In this way, when installing the air diffuser 70 and the supply unit 52 in a deep water tank, the fixing bracket 63 can also play the role of a guide, making installation easy. In addition, the floating prevention member 62 may be connected to the fixing bracket 63 to fix the supply unit 52 and the fixing bracket 63. In this way, the tank bottom surface 515 and the supply unit 52 are connected through the fixing bracket 63, and floating of the supply unit due to buoyancy is prevented.

[0031] As shown in Figs. 12 to 14, the gas supply body 10 may have a folded structure (which may be called a folded structure, folded structure, or pleated structure) so as not to interfere with the upward and downward fluid flow generated by the air discharged from the air diffuser 70. Figs. 12 to 14 are top views of the gas supply body 10. The folding direction is horizontal. By doing so, the number of air supply and exhaust manifold branching parts and air supply and exhaust tubes can be reduced without interfering with the fluid flow, thereby reducing costs. As shown in Fig. 13, one supply body unit 52 may be configured with one gas supply body 10 that is folded back continuously. In this case, the air supply manifold may not be used, and the air supply tube 11a may be directly connected to the air supply pipe and blower. Similarly, the exhaust manifold may not be used, and the exhaust tube 14a may be directly connected to the exhaust pipe.

[0032] The distance between the folded surfaces is preferably 5 mm or more to ensure the flow of fluid between the membrane surfaces, and is preferably 200 mm or less from the viewpoint of the packing rate per unit volume.

[0033] The distance from one fold to the next fold in the fold structure is desirably 100 mm or more in order to ensure a flat surface of the gas supplier, and is desirably 3000 mm or less in order to make the external dimensions of the supplier unit large enough to be transported.

[0034] There is no particular limit to the folding angle of the folded structure, but it is preferable that it is 90 degrees or 180 degrees (U- or V-shape). Figures 12 and 13 show an example where the folding angle is 180 degrees, and Figure 14 shows an example where the folding angle is 90 degrees. This can increase the packing rate per unit volume.

[0035] The distance between the supply unit 52 in the vertical direction of the tank is desirably 4500 mm or less. If the distance between the ends is long, the rocking load caused by the air diffusion becomes large, and there is a concern that the end of the gas supply 10 may be damaged.

[0036] The length of the long side of the gas supplier 10, i.e., the total path length through which the gas flows inside the gas supplier, is desirably 500 m or less. If the pressure loss when the gas flows inside the gas supplier is large, a blower with high discharge performance must be used, which increases energy costs.

[0037] (Gas supplier 10) As shown in Figs. 9A and 9B, each gas supplier 10 is a structure that, while immersed in the wastewater W of the wastewater treatment tank 51, supplies gas supplied from the gas supplier air supply port 11 into the wastewater W and exhausts excess gas from the gas supplier exhaust port 14. The gas supplier 10 includes a gas supply layer 12 and a waterproof gas-permeable membrane 21 in addition to the air supply port 11 and the exhaust port 14. In the internal space of the gas supplier 10, a part of the air supply tube 11a of the air supply unit 30 is inserted into the air supply port 11. Gas (air, oxygen) is supplied from the air supply unit 30 to the internal space of the gas supplier 10. In addition, a part of the exhaust tube 14a of the exhaust unit 40 is inserted into the exhaust port 14. The gas (air, oxygen) exhausted from the exhaust port 14 is exhausted to the outside of the wastewater treatment tank 51 from the exhaust unit 40. Moreover, the condensed water generated inside the gas-sending layer 12 is discharged from the internal space of the gas supply body 10 to the outside through the exhaust part 40 .

[0038] As shown in Figs. 11 to 14, each gas supplier 10 is a flat plate member (Fig. 11) or a folded flat plate member (Figs. 12 to 14), and is arranged so that the surface is developed along the vertical direction (depth direction) and the lateral direction (horizontal direction). This efficiently ensures a contact area with the wastewater W. Also, by arranging each gas supplier 10 so that the side of each gas supplier 10 is parallel to the straight line connecting the wastewater inlet 51a and the outlet 51b, the wastewater W supplied from the inlet 51a into the wastewater treatment tank 51 can smoothly flow toward the outlet 51b. On the other hand, when the aeration device 70 is sufficiently agitated, the positional relationship between the wastewater inlet 51a and the outlet 51b does not necessarily need to be maintained. The number of gas suppliers 10 constituting the supplier unit 52 does not necessarily need to be plural, and may be single.

[0039] If the interval between the gas supply bodies 10 is defined as "the interval between the outer surfaces of two adjacent gas supply bodies 10, not including the thickness of the gas supply body 10," the interval between the gas supply bodies 10 is preferably 5 mm or more and 200 mm or less. If the interval between the gas supply bodies 10 is less than 5 mm, clogging may occur due to microorganisms growing on the waterproof air-permeable membrane 21. If the interval between the gas supply bodies 10 exceeds 200 mm, the contact efficiency with the wastewater may deteriorate, and it may be difficult to improve the wastewater treatment performance. In order to reliably avoid the above problems, it is more preferable to set the interval between the gas supply bodies 10 to 8 mm or more and 50 mm or less.

[0040] Fig. 9B is a vertical cross-sectional view of the gas supply body 10. As shown in Fig. 9B, the gas supply body 10 includes a gas-transporting layer 12 and a waterproof, gas-permeable membrane 21, and the gas-transporting layer 12 is disposed in a bag formed by the waterproof, gas-permeable membrane 21. The bag-shaped waterproof, gas-permeable membrane 21 may be folded, or two waterproof, gas-permeable membranes 21, 21 may be overlapped and the ends of these waterproof, gas-permeable membranes 21, 21 may be bonded together. The gas-transporting layer 12 is disposed between the two waterproof, gas-permeable membranes 21.

[0041] (Air supply unit 30) The air supply unit 30 supplies gas to the internal space of the gas supplier 10. The air supply unit 30 includes a blower, an air supply pipe, an air supply manifold 35, an air supply manifold branching section 35a, and an air supply tube 11a. The air supply pipe (not shown) is a pipe that supplies air (oxygen) sent from a blower (not shown) to the air supply manifold 35. The blower is placed in the atmosphere. The air supply manifold 35 may be placed underwater. The air supply pipe connected to the blower from the air supply manifold 35 may rise above the water surface from underwater. The air supply manifold 35 is connected to the air supply pipe at one end and to the air supply manifold branching section 35a at the other end. In addition, when the membrane area of ​​one gas supplier 10 is large and branching by the manifold 35 is not necessary, the gas supplier air supply port 11 and the air supply pipe may be directly connected. A part of the air supply unit 30 may be installed under the water surface of the treatment tank 51 in which the wastewater W is stored. The part installed under the water surface may be any of the manifold 35, the air supply pipe, or the piping path connecting the members constituting the air supply unit 30. The material of the air supply unit 30 may be metal or resin.

[0042] When the air supply manifold 35 is installed underwater, the joint between the air supply manifold 35 and the air supply manifold branch 35a must be completely sealed. The joining method is not particularly limited as long as it can achieve a complete seal, but screwing, welding, or adhesive bonding is preferable. In addition, the joint between the air supply manifold branch 35a and the air supply tube 11a must also be completely sealed. The joining method is not particularly limited as long as it can achieve a complete seal.

[0043] (Exhaust section 40) The exhaust unit 40 exhausts the excess gas from the gas supplier 10 to the outside of the gas supplier 10. The exhaust unit 40 includes an exhaust tube 14a, an exhaust manifold branch 45a, an exhaust manifold 45, and an exhaust pipe. The exhaust pipe (not shown) exhausts the exhaust air collected in the exhaust manifold to the outside of the wastewater treatment system 100. The exhaust manifold 45 is connected to the exhaust pipe at one end and to the exhaust manifold branch 45a at the other end. As in the air supply unit 30, in the exhaust unit 40, when the membrane area of ​​one gas supplier 10 is large and branching by the manifold 45 is not necessary, the gas supplier exhaust port 14 and the exhaust pipe may be directly connected. A part of the exhaust unit 40 may be installed under the water surface of the treatment tank 51 in which the water W is stored. The part installed under the water surface may be any of the manifold 45, the exhaust pipe, and the piping path connecting the members constituting the exhaust unit 40. The material of the exhaust portion 40 may be metal or resin.

[0044] The gas supplied into the wastewater W via the gas supplier 10 is a gas containing oxygen in order to promote activation of aerobic microorganisms in the wastewater W. Specifically, the gas may be air or pure oxygen.

[0045] (Waterproof and air permeable membrane 21) The waterproof air-permeable membrane 21, when immersed in the liquid (wastewater) so that the outermost layer is in contact with the liquid (wastewater), allows oxygen supplied to the inside (gas-sending layer 12 side) to permeate outward, thereby supplying oxygen into the liquid (wastewater). When the gas supplier 10 is immersed in the wastewater treatment tank 51, the waterproof air-permeable membrane 21 has a characteristic of allowing air to permeate from the inside (gas-sending layer 12) to the outside (wastewater W) and not allowing wastewater to permeate from the outside (wastewater W) to the inside (gas-sending layer 12). As a result, aerobic microorganisms in the wastewater W gather on the surface 21a of the waterproof air-permeable membrane 21 to which air (oxygen) is continuously supplied. Thus, the microorganisms attach to the surface of the waterproof air-permeable membrane 21, forming a biofilm. Then, by the action of the microorganisms contained in the wastewater W or held on the surface, the microorganisms dissolved or dispersed in the water, or the nitrogen compounds, are decomposed, and the wastewater is purified.

[0046] 9B, the waterproof air-permeable membrane 21 includes a substrate 211 and a gas-permeable imperforate layer 212. In the illustrated example, the waterproof air-permeable membrane 21 is formed by laminating the substrate 211 and the gas-permeable imperforate layer 212 in this order.

[0047] (Base material 211) The substrate 211 is a microporous film made of a thermoplastic resin. The microporous film is a film having a large number of fine through holes. The material of the substrate 211 may include a polymer material selected from fluororesins including polyolefin, polystyrene, polysulfone, polyethersulfone, polyarylsulfone, polymethylpentene, polytetrafluoroethylene, and polyvinylidene fluoride, silicone-based polymers including polybutadiene and poly(dimethylsiloxane), and copolymers of these materials.

[0048] The method for producing the substrate 211, which is a microporous membrane, is not particularly limited, but the substrate 211 can be produced by, for example, a phase separation method, a stretching hole-opening method, a melting recrystallization method, a powder sintering method, a foaming method, or a solvent extraction. The substrate 211 may also be a self-assembled honeycomb microporous membrane.

[0049] The thickness of the substrate 211 is preferably 10 μm to 500 μm, and more preferably 50 μm to 200 μm. The thickness of the substrate 211 is a value measured according to JIS1913:2010 General Nonwoven Fabric Testing Method 6.1 Thickness Measurement Method.

[0050] The pore diameter of the substrate 211 is preferably 0.01 μm to 50 μm from the viewpoint of preventing defects in the gas-permeable non-porous layer, and more preferably 0.1 μm to 30 μm from the viewpoint of maintaining high strength and gas permeability. The pore diameter is determined by observing the surface with a scanning electron microscope (SEM) and using the following method from the observed image. The observation magnification can be any magnification as long as the pore diameter of the object to be observed can be calculated appropriately.

[0051] (Method of determining pore size) The images obtained by SEM observation are binarized and the pore diameter is calculated by image analysis. When calculating, the pore diameter is approximated by an ellipse, the length of the major axis of the ellipse is regarded as the pore diameter, and the average value is evaluated.

[0052] Alternatively, the pore size of the substrate 211 is defined as the average pore size obtained from pore size distribution measurement (perm porosimetry) by capillary condensation method. In perm porosimetry, the relationship between the differential pressure between atmospheric pressure and the measured pressure and the gas permeation flow rate is obtained from the gas permeation flow rate measured while gradually increasing the measured pressure of the gas applied to the sample. To obtain the pore size, a wet curve is measured on a wet sample after the sample is immersed in a wetting liquid with a known surface tension, and a dry curve is measured on a dried sample. By gradually increasing the pressure in each case within a predetermined pressure range, information on the through pore size in the sample can be obtained. The average pore size is obtained by finding the point X where the wet curve and a curve with a slope of 1 / 2 that of the dry curve (half dry curve) intersect, and substituting this into the equation, d=2860×γ / DP. In the above equation, d is the average pore size (mm), γ is the surface tension of the wetting liquid (dynes / cm), and DP is the differential pressure (Pa) between the atmospheric pressure and the gas pressure at point X. Measurements can be performed using a Perm Porometer (CFP-1500-AEC) manufactured by Porous Materials. Test conditions include, for example, test temperature at room temperature (20°C ± 5°C), wetting liquid at Galwick (surface tension 15.7 dynes / cm), pressurized gas at compressed air, sample diameter at 33 mm, maximum supply pressure at 250 psi, and differential pressure rise rate at 4 psi / min. When preparing a wet sample, the wetting liquid in which the sample is immersed can be placed in a desiccator and degassed to thoroughly wet the sample.

[0053] (Gas-permeable non-porous layer 212) The gas-permeable non-porous layer 212 is a layer that has pores with a smaller pore diameter than the pores of the substrate, or has pores with an undetectable diameter, and is permeable to gas. The pore diameter of the gas-permeable non-porous layer 212 can be measured in the same manner as the pore diameter of the substrate 211. On the other hand, the gas-permeable non-porous layer 212 does not allow liquid to pass through. The liquid is, for example, water or wastewater W.

[0054] Examples of the gas that permeates the gas-permeable non-porous layer 212 include oxygen, carbon dioxide, nitrogen, hydrogen, alcohols such as methanol and ethanol, organic solvents, and mixed gases thereof. From the viewpoint of effectively growing and activating microorganisms, the gas is preferably oxygen or a mixed gas containing oxygen. Gas permeability can be measured by a method specified in JIS K 7126.

[0055] The gas-permeable non-porous layer 212 may be a thermoplastic resin or a thermosetting resin. The thermosetting resin may be a resin that cures by heat or by irradiation with ultraviolet light. It may also be a resin that cures by organic peroxide crosslinking, addition reaction crosslinking, or condensation crosslinking.

[0056] The material of the gas-permeable non-porous layer 212 may include a thermosetting polymer selected from polyolefin, polymethylpentene, polystyrene, polysulfone, polyethersulfone polytetrafluoroethylene, acrylic resin, polyurethane resin, and copolymers of these materials. Also, a silicone-based silicone resin such as poly(dimethylsiloxane) having a siloxane skeleton of (Si-O-Si)n (n=integer) can be used. Among these, it is particularly preferable to use a urethane resin or a silicone resin.

[0057] Examples of the polyurethane resin that can be used include "Asaflex 825" (manufactured by Asahi Kasei Corporation), "Pellethene 2363-80A", "Pellethene 2363-80AE", "Pellethene 2363-90A", and "Pellethene 2363-90AE" (all manufactured by The Dow Chemical Company), and "Heimullen Y-237NS" (manufactured by Dainichiseika Color & Chemicals Co., Ltd.).

[0058] The silicone resin or silicone polymer, or the silicone resin composition for obtaining them, may be blended or composed without any particular limitation. The monomer used in the silicone resin composition may be monofunctional, difunctional, trifunctional, or tetrafunctional, and may be used alone or in combination of two or more kinds. The monomer may be a halogenated alkylsilane, an unsaturated group-containing silane, an aminosilane, a mercaptosilane, or an epoxysilane. Examples of the monomer that may be used include monomers represented by the following chemical formulas: HSiCl3, SiCl4, MeSiHCl2, Me3SiCl, MeSiCl3, Me2SiCl2, Me2HSiCl, PhSiCl3, Ph2SiCl2, MePhSiCl2, Ph2MeSiCl, CH2=CHSiCl3, Me(CH2=CH)SiCl2, Me2(CH2=CH)SiCl, (CF3CH2CH2)MeSiCl 2、 (CF3CH2CH2)SiCl3, CH 18 H 37SiCl3 (in the chemical formula, "=" represents a double bond, "Me" represents a methyl group, and "Ph" represents a phenyl group). The monomers may be used alone or in combination of two or more. As other organic groups, alkyl groups such as propyl, isopropyl, butyl, isobutyl, tert-butyl, hexyl, octyl, and decyl groups; aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups; cycloalkyl groups such as cyclopentyl and cyclohexyl groups; and aralkyl groups such as benzyl, 2-phenylethyl, and 3-phenylpropyl groups may be used. Among these, methyl, phenyl, or a combination of both are preferred. This is because the components that are methyl, phenyl, or a combination of both are easy to synthesize and have good chemical stability. In addition, when a polyorganosiloxane with particularly good solvent resistance is to be used, it is preferable that the methyl, phenyl, or a combination of both is further combined with a 3,3,3-trifluoropropyl group. In addition, the silicone resin composition may contain an organoalkoxysilane. Examples of organoalkoxysilanes include compounds represented by the following chemical formulas, which may be used alone or in combination of two or more: Me3SiOCH3, Me2Si(OCH3)2, MeSi(OCH3)3, Si(OCH3)4, Me(C2H5)Si(OCH3)2, C2H5Si(OCH3)3, C 10 H 21 Si(OCH3)3, PhSi(OCH3)3, Ph2Si(OCH3)2, MeSiOC2H5, Me2Si(OC2H5)2, Si(OC2H5)4, C2H5Si(OC2H5)3, PhSi(OC2H5)3, Ph2Si(OC2H5)2.

[0059] Furthermore, the silicone resin composition may contain an organosilanol. Examples of the organosilanol include compounds represented by the following chemical formulas, which may be used alone or in combination of two or more: Me3SiOH, Me2Si(OH)2, MePhSi(OH)2, (C2H5)3SiOH, Ph2Si(OH)2, and Ph3SiOH.

[0060] The reaction method for obtaining the silicone polymer used in the silicone resin may include, for example, hydrolysis of chlorosilane, ring-opening polymerization of cyclic dimethylsiloxane oligomer, etc. Examples of the polymer to be used include dimethyl polymers, methylvinyl polymers, methylphenylvinyl polymers, methylfluoroalkyl polymers, etc.

[0061] The method of curing the silicone polymer, that is, the method of reacting (vulcanizing) to obtain a silicone resin, is not particularly limited. Heat vulcanization or room temperature vulcanization may be used. Either a millable type silicone resin composition or a liquid rubber type silicone resin composition may be used as the state before the reaction. A polymer having a degree of polymerization of about 4000 to 10000 is preferably used as the polymer used in the millable type silicone resin composition. In addition, it may be a one-liquid type or a two-liquid type. As the reaction method, for example, a dehydration condensation reaction between silanol groups (Si-OH), a condensation reaction between a silanol group and a hydrolyzable group, a reaction of a methylsilyl group (Si-CH3) or a vinylsilyl group (Si-CH=CH2) with an organic peroxide, an addition reaction between a vinylsilyl group and a hydrosilyl group (Si-H), a reaction with ultraviolet light, a reaction with an electron beam, etc. may be used.

[0062] (Gas delivery layer 12) FIG. 10 is a perspective view showing the gas sending layer 12. The gas sending layer 12 is a member that holds a space inside the gas supply body, and is made of paper, resin, or metal. Any member that does not change shape significantly due to water pressure may be used, and the waterproof and air-permeable membrane and the sending layer may form a partitioned space. Examples of the structure of the member that holds a space inside the gas supply body include a mesh shape, a hollow shape, a tricot knit shape, and a raschel knit shape. The gas sending layer 12 may be a mesh shape as shown in FIG. 10. The gas sending layer 12 is a structure having a gas flow path that can send out the gas supplied from the first end side in any direction. The gas from the gas supply body air supply port 11 is supplied to one end of the gas sending layer 12. The gas sending layer 12 has a gas flow path that sends out the supplied gas, and releases the gas from the gas supply body exhaust port 14 at the other end. There is no particular limitation on the positional relationship between the gas supply outlet 11 and the exhaust outlet 14 of the gas supply body, but it is preferable that they are located at separate positions within the gas supply body.

[0063] There is no particular restriction on the thickness of the gas-delivery layer 12, but since the thicker the gas supply body 10, the lower the membrane filling efficiency relative to the tank volume, it is preferable that the gas-delivery layer 12 is thinner. Specifically, the thickness is preferably 3 mm or less, more preferably 1.5 mm or less. On the other hand, if the thickness of the gas-delivery layer 12 is too thin, it is not possible to ensure sufficient space inside the gas supply body. Specifically, the thickness is preferably 0.2 mm or more, more preferably 0.4 mm or more.

[0064] The materials that make up the gas-delivery layer 12 include paper, ceramic, aluminum, iron, stainless steel, plastics (polyolefin resin, polystyrene resin, polyester resin, polyvinyl chloride resin, acrylic resin, urethane resin, epoxy resin, polyamide resin, methyl cellulose resin, ethyl cellulose resin, polyvinyl alcohol resin, vinyl acetate resin, phenolic resin, fluororesin, and polyvinyl butyral resin), etc.

[0065] In addition, because of their excellent strength, the material of the gas-transporting layer 12 is preferably paper, aluminum, stainless steel, iron, polyolefin resin, polystyrene resin, PVC resin, or polyester resin.

[0066] From the viewpoint of keeping material costs low, it is preferable to use, as the material for the gas-sending layer 12, for example, paper, resins such as polyolefin, polystyrene, PVC, and polyester, and metals such as aluminum.

[0067] (Diffuser 70) The wastewater treatment system 50 of the present disclosure further includes an aeration system 70 . The air diffuser 70 is a device that supplies gas (air) from outside the wastewater treatment tank 51 to the wastewater treatment tank 51 to agitate (aerate) the wastewater. The gas is supplied from the air supply pipe 31 separately from the gas supplied to the inside of the gas supplier 10. The gas supplied by the air diffuser 70 may be supplied from a common supply source to the gas supplied to the inside of the gas supplier 10. The air diffuser 70 includes an air diffuser pipe 71 and an air diffusion blower.

[0068] The air diffuser 70 has an air diffuser pipe 71 disposed below the supplier unit 52 or the gas supplier 10. As shown in Fig. 4, an upward flow generated by air supply from the air diffuser 70 rises between the gas suppliers of the supplier unit, and forms a downward flow between the wastewater treatment devices 50 or between the wastewater treatment device 50 and the water tank wall. This forms a swirling flow centered on the wastewater treatment device 50 in the tank, cleaning the membrane surface and mixing the wastewater.

[0069] To form a swirling flow, it is necessary to appropriately install the wastewater treatment device 50. Specifically, as shown in Fig. 5, if the distance from the top of the gas supplier 10 of the wastewater treatment device 50 to the water surface is H1, the installation position is set so that H1 is at least 100 mm or more, preferably 250 mm or more, and more preferably 500 mm or more.

[0070] 6, if the distance between the end of the gas supplier 10 of the wastewater treatment device 50 in the vertical direction to the membrane surface and the side wall of the water tank is W1, W1 is set at a distance of at least 100 mm, preferably 250 mm or more, and more preferably 380 mm or more. On the other hand, if W1 is 1800 mm or more, stagnation areas that cannot be reached by the swirling flow will occur, so W1 is set to be less than 1800 mm, preferably less than 1100 mm, and more preferably less than 680 mm.

[0071] 5 and 6, when multiple wastewater treatment devices 50 are installed, if the horizontal distance between the ends of adjacent wastewater treatment devices 50 in the vertical direction to the membrane surface of the gas supplier 10 is W2, the devices are installed at a distance of at least 100 mm, preferably 250 mm or more, and more preferably 430 mm or more. On the other hand, if W2 is 1800 mm or more, stagnation areas that cannot be reached by the swirling flow will occur, so the devices are installed so that W2 is less than 1800 mm, preferably less than 1200 mm, and more preferably less than 730 mm.

[0072] 6, if the distance between the end of the gas supplier of the wastewater treatment device 50 in the direction parallel to the membrane surface and the side wall of the water tank is D1, there is no particular limit to D1, but it is preferable to set it so that D1 is as small as possible, taking into consideration the connection and maintenance of the air supply unit, exhaust unit, and fixing metal fittings. This makes it possible to reduce the dead space where no upward flow originating from the air diffuser occurs.

[0073] When multiple wastewater treatment devices 50 are installed, if the distance between the ends parallel to the membrane surface of the gas supplier of adjacent wastewater treatment devices 50 is D2, then, similar to D1, it is preferable to install them so that the possible range D2 is as small as possible, taking into consideration the connection and maintenance of the air supply section, exhaust section, and fixing brackets.

[0074] (Diffuser pipe 71) The air diffuser 71 supplies air to the wastewater treatment tank 51, causes the wastewater W stored in the wastewater treatment tank 51 to flow, and makes the concentration of organic matter or nitrogen source in the wastewater W uniform. In addition, the air diffuser 71 peels off the biofilm excessively attached to the gas supply body, and prevents the gap between the gas supply bodies from being blocked by the biofilm. The arrangement of the air diffuser 71 and the air discharge section 71a is shown in FIG. 7. In this embodiment, the air diffuser 71, particularly the air discharge section 71a of the air diffuser 71, is arranged at the lower part of the gas supply body 10. In this way, the biofilm attached to the gas supply body 10 is effectively washed by the air bubbles generated from the air diffuser. Under this condition, the air discharge section 71a may be one or more. Also, the air diffuser 71 may be one or more.

[0075] Although it is called an air diffuser for convenience, the shape of the air diffuser 71 is not particularly limited, and it may be any shape such as a circular, cylindrical, plate-shaped, aerator-type, etc. The material of the air diffuser 71 is not particularly limited, and it may be any material such as stainless steel, polyethylene, polyvinyl chloride, PTFE rubber, EPDM rubber, silicone rubber, etc. Examples of the shape of the air diffuser 71 are shown in Figs. 8A to 8D. In Fig. 8A, the air diffuser 71 is distributed from the main pipe to multiple branch pipes, and an air discharge part 71a is formed in each branch pipe. In Fig. 8B, two air diffusers 71 are connected in parallel, and the air discharge part 71a is formed without passing through a branch pipe. In Fig. 8C, the air discharge part 71a is formed on the entire surface of the plate-shaped air diffuser 71. In Fig. 8D, multiple disk-shaped air diffusers 71 are connected, and the air discharge part 71a is formed on the entire surface. In this way, there is no limit to the shape, number, or connection method as long as the structure can generate air bubbles from the lower part of the gas supply body.

[0076] (Aeration Blower 72) The aeration blower 72 (not shown) supplies air to the aeration pipe 71. There is no limit to the type of the aeration blower 72 as long as it has a discharge pressure equal to or greater than the water pressure, and any type such as a Roots type, turbo type, or radial type may be used. The aeration blower 72 and the aeration pipe 71 are connected by piping, and a valve, a flow meter, or the like may be installed as necessary. There is no particular limit to the method of controlling the discharge speed from the aeration blower 72, and any method such as an inverter or bypass piping may be used.

[0077] The amount of air discharged from the aeration pipe 71 is the aeration intensity (m 3 / m 3 / h). The aeration intensity is expressed as the amount of air discharged from the aeration pipe 71 per unit time (m 3 / h) is the water volume (m 3 From the viewpoint of mixing of wastewater, if the aeration strength is low, there is a concern that the aeration of the wastewater W may be insufficient. The lower limit of the aeration strength is determined comprehensively based on the solids concentration in the wastewater W, the viscosity of the wastewater W, etc., but should be at least 0.1 (m 3 / m 3 In particular, when the solid content of the wastewater W is high or the solid content has a high sedimentation tendency, the flow rate is preferably at least 0.5 (m 3 / m 3 From the viewpoint of cleaning the microbial film attached to the membrane surface, the higher the aeration intensity, the greater the cleaning effect. The lower limit of the aeration intensity when cleaning the microbial film is determined individually depending on the properties of the microbial film, but it is preferable that it is at least 0.5 (m 3 / m 3 / h) or more is preferable. Note that the aeration intensity during cleaning is at least twice as high as the aeration intensity during wastewater mixing, as this makes it easier for the microbial film that has stably adhered in the aeration state during wastewater mixing to peel off, and thus exerts a cleaning effect. Note that aeration during cleaning and aeration during wastewater mixing do not necessarily have to be continuous aeration, and aeration may be intermittent depending on the individual microbial film and the state of the wastewater. Intermittent aeration can reduce power consumption and lead to reduced running costs.

[0078] Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims. [Explanation of symbols]

[0079] 10 Gas supply 11 Air outlet 11a Air supply tube 12 Gas Delivery Layer 14 Exhaust port 14a Exhaust tube 21 Waterproof and air permeable membrane 30 Air supply section 35 Air supply manifold 35a Air supply manifold branch 40 Exhaust section 45 Exhaust manifold 45a Exhaust manifold branch 45a 50 Wastewater treatment equipment 51 Wastewater treatment tank 51a Wastewater inlet 51b Wastewater outlet 61 Support 62 Anti-floating member 63 Fixing bracket 52 Supplier Unit 70 Air diffuser 71 Air diffuser 71a Air outlet 100 Wastewater Treatment System 211 Base material 212 Gas-permeable non-porous layer 511~514 Side 515 Bottom

Claims

1. A wastewater treatment device that purifies wastewater by utilizing the action of microorganisms in the wastewater, The wastewater treatment device includes a feeder unit, The supply unit has a waterproof, gas-permeable gas supply unit, The gas supply defines a compartment space separated from the wastewater, A wastewater treatment device in which a gas or wastewater-derived fluid or solid is arranged between two adjacent membrane surfaces of two adjacent gas suppliers, or between two membrane surfaces of one gas supplier that contacts the wastewater.

2. The wastewater treatment device according to claim 1 , further comprising an air diffuser, the air diffuser being installed below the gas supplier.

3. 3. The wastewater treatment device according to claim 1, wherein the gas supply body has a folded structure folded back in a horizontal direction, and a membrane surface of the gas supply body extends in a vertical direction.

4. 3. The wastewater treatment device according to claim 1, wherein the gas supply body has a folded structure folded back in a horizontal direction, and the distance between adjacent membrane surfaces is 5 mm or more and 200 mm or less.

5. The wastewater treatment device according to claim 4, wherein the length from one folded portion to the next folded portion is defined as a folding unit, and the folding unit length is 100 mm or more and 3000 mm or less.

6. The wastewater treatment device according to claim 3, wherein the angle of the folded portion is 90 degrees or less and 180 degrees or less.

7. The wastewater treatment device according to claim 1 or 2, wherein a vertical distance of the gas supplier is 2500 mm or less.

8. 3. The wastewater treatment device according to claim 1, wherein a total horizontal path between vertical end points of the fractionation space in the gas supply body is 500 m or less.

9. The wastewater treatment device according to claim 1 or 2, wherein the gas suppliers are installed in multiple stages, one above the other.

10. A wastewater treatment method in which a gas supplier is placed in a treatment tank and the wastewater is purified by utilizing the action of microorganisms in the wastewater, comprising: The gas supplier forms a space separated from the wastewater by a waterproof and air-permeable membrane, The gas supply body has at least one repeated structure of mountain folds and valley folds when viewed from above, The treatment tank has at least one wastewater inlet and at least one wastewater outlet; The wastewater treatment is performed from the wastewater inlet to the wastewater outlet. Wastewater treatment methods.

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