JP2024048276A - Wastewater Treatment Equipment - Google Patents

Abstract

[Problem] In a wastewater treatment device that activates microorganisms in wastewater and purifies the wastewater with the microorganisms, the contact time between the wastewater and a gas supplier is ensured and the wastewater treatment performance is improved. [Solution] A wastewater treatment device 100 includes a wastewater treatment tank 51 having four side walls arranged on the four sides of a rectangle, the wastewater treatment tank having an inlet arranged on one side wall for introducing wastewater into the wastewater treatment tank and an outlet arranged on a side wall opposite the one side wall for discharging wastewater from the wastewater treatment tank, and a supplier unit 52 installed in the wastewater treatment tank, the supplier unit including a plurality of gas suppliers 10, each of which has a gas permeable membrane and is a flat plate-shaped member, and the plurality of gas suppliers are arranged along the longitudinal direction in a plan view. The distance between one of the four side walls of the wastewater treatment tank and the gas supplier adjacent to the side wall is 5 mm to 1000 mm. [Selected Figure] Figure 1

Description

This article relates to an aerobic biological treatment device suitable for aerobic biological treatment of organic wastewater, and in particular to an aerobic biological treatment device that employs the MABR (membrane aeration bioreactor) method, which uses an oxygen-permeable membrane to dissolve oxygen in the water to be treated in a reaction tank.

Conventionally, devices have been proposed that purify wastewater by utilizing the activity of microorganisms contained in the wastewater. One such type of wastewater treatment device uses flat membranes to treat organic matter in the wastewater. In such wastewater treatment devices, it is important that the wastewater flows smoothly from the inlet to the outlet (Patent Document 1).

Patent Publication 2019-205971

However, in wastewater treatment devices such as those described above, specific consideration has not been given to the positional relationship between the supplier units, the positional relationship between the wastewater treatment tank and the supplier unit, and the positional relationship between the inlet and the outlet, which are important for wastewater treatment. Therefore, when applied to an actual wastewater treatment device, a problem with the conventional technology is that, for example, if the supplier units are designed with a large distance between them or the supplier unit is designed with a large distance between the wastewater treatment tank, a short-circuit flow occurs, shortening the contact time between the inflowing wastewater and the gas supplier, resulting in a decrease in wastewater treatment performance. The present disclosure aims to solve at least one of these problems.

This disclosure has been made to solve the above problems, and aims to improve treatment efficiency by increasing the contact efficiency between the inflowing wastewater and the gas supplier.

A wastewater treatment system according to a first aspect is a wastewater treatment device that supplies oxygen that has permeated a gas-permeable membrane to wastewater stored in a wastewater treatment tank, thereby activating microorganisms in the wastewater and purifying the wastewater through the activity of the microorganisms,
A wastewater treatment tank having four side walls arranged on the four sides of a rectangle, the wastewater treatment tank having an inlet arranged on one side wall for introducing wastewater into the inside of the wastewater treatment tank, and an outlet arranged on a side wall opposite to the one side wall for discharging wastewater from the wastewater treatment tank;
A supply unit installed in the wastewater treatment tank, the supply unit including a plurality of gas supply bodies, each of the gas supply bodies having a gas permeable membrane and being a flat plate-shaped member, the plurality of gas supply bodies being arranged along a longitudinal direction in a plan view;
Equipped with
The distance between one of the four side walls of the wastewater treatment tank and the gas supplier adjacent to the side wall is 5 mm or more and 1000 mm or less.

The wastewater treatment device of the second aspect is the wastewater treatment device of the first aspect, in which two or more supplier units are installed within one wastewater treatment device, and the distance between adjacent supplier units is 0 mm or more and 1000 mm or less.

The wastewater treatment device of the third aspect is the wastewater treatment device of the first aspect, in which at least one of the inlets is disposed in the wastewater treatment tank such that the height from the ground where the inlet is disposed in the side wall is different from the height from the ground where the outlet is disposed in the side wall.

The wastewater treatment device of the fourth aspect is the wastewater treatment device of the first aspect, in which the distance between adjacent gas suppliers 10 in the wastewater treatment tank is 5 mm or more and 200 mm or less.

The wastewater treatment device of the fifth aspect is the wastewater treatment device of the first aspect, in which at least one baffle plate is disposed in the wastewater treatment tank to obstruct the flow of wastewater from the inlet to the outlet, and the baffle plate is disposed vertically to the water surface.

The wastewater treatment device of the sixth aspect is the wastewater treatment device of the fifth aspect, wherein two or more of the supplier units are installed within one wastewater treatment device, the baffle plate is installed between two supplier units, and the baffle plate is arranged in contact with one of the four side walls of the wastewater treatment tank.
The wastewater treatment device of the seventh aspect is a wastewater treatment device of any of the first to sixth aspects, wherein inside the wastewater treatment tank, near the side wall on which the inlet is installed, a submerged weir for directing the flow of wastewater downward is installed, and inside the wastewater treatment tank, near the side wall on which the outlet is installed, an overflow weir for equalizing the flow of wastewater.

The wastewater treatment system disclosed herein can prevent short-circuiting of wastewater flowing into the wastewater treatment tank, thereby preventing a decrease in treatment efficiency.

1 is a vertical cross-sectional view of a wastewater treatment device 100 according to a first embodiment. 1 is a vertical cross-sectional view of a wastewater treatment device 100 according to a first embodiment. 1 is a horizontal cross-sectional view of a wastewater treatment device 100 according to a first embodiment. 2 is a vertical cross-sectional view of the gas supply body 10. FIG. FIG. 5 is a perspective view showing the gas delivery layer 12 constituting the gas supplier 10 of FIG. 4. 1 is a schematic side view of a wastewater treatment device 100 according to a first embodiment, as viewed from the same direction as the vertical sectional view of FIG. 1 is a diagram showing a schematic diagram of microorganisms decomposing organic matter in wastewater W using a gas supplier 10. FIG. 1 is a diagram showing a state in which water has accumulated in the internal space of gas supply bodies 10a and 10b and is being discharged. FIG. FIG. 8B shows the state of the gas supply bodies 10a and 10b after FIG. 8A. 4 is a diagram showing an orifice portion 47a in the liquid supply tube 41. FIG. 4 is a diagram showing a multiple-hole orifice portion 47b in the liquid supply tube 41. FIG. 13 is a diagram showing a constriction portion 47c in the liquid supply tube 41. FIG. 13 is a diagram showing a curved portion 47d in the liquid supply tube 41. FIG. 13 is a diagram showing a portion in the liquid supply pipe 41 where a communicating porous member 47e is arranged. FIG. FIG. 11 is a plan view of a wastewater treatment device 100 according to a second embodiment. FIG. 11 is a plan view of the wastewater treatment device 100 according to the third embodiment. FIG. 11 is a plan view of the wastewater treatment device 100 according to the fourth embodiment. FIG. 13 is a vertical cross-sectional view of the wastewater treatment device 100 of the fifth embodiment. FIG. 13 is a vertical sectional view of the wastewater treatment device 100 of the sixth embodiment.

First Embodiment
(Wastewater treatment device 100)
The wastewater treatment device 100 of this embodiment utilizes the action of aerobic 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 Figures 1 to 3, the wastewater treatment device 100 includes a wastewater treatment tank 51 and a wastewater treatment system 50.

(Wastewater treatment tank 51)
1 to 3, the wastewater treatment tank 51 is a bottomed container in which wastewater W is stored. As shown in Fig. 3, the wastewater treatment tank 51 has a rectangular shape when viewed from above. The wastewater treatment tank 51 has four side walls 511 to 514 and a bottom surface 515. An inlet 51a for the wastewater W is disposed in the side wall 511, and an outlet 51b for the wastewater W is disposed in a side wall 512 opposite the side wall 511.
In this embodiment, as shown in Fig. 2, the inlet 51a and the outlet 51b are arranged so that they are at the same height from the ground (depth from the water surface). As will be described later in the fifth and sixth embodiments, the inlet 51a and the outlet 51b may be arranged so that they are at different heights from the ground. In this case, the residence time of the wastewater W in the tank increases, so that the short-circuit flow of the wastewater W is prevented and the wastewater W can be brought into contact with the gas supplier 10 more efficiently.
A plurality of inlets 51 a and outlets 51 b may be provided. By providing a plurality of inlets 51 a and outlets 51 b, the contact efficiency between the wastewater W and the gas supplier 10 is improved, which is more preferable.

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

The volume of the wastewater treatment tank is not particularly limited, but may be, for example, from ¹ m3 to ^10,000 m3.

(Wastewater Treatment System 50)
The wastewater treatment system 50 includes a supplier unit 52. The wastewater treatment system 50 may further include an air supply unit and a liquid supply unit 40.

(Supplier unit 52)
6, the supplier unit 52 is a unitized gas supplier 10, and is disposed inside the wastewater treatment tank 51. The supplier unit 52 includes a plurality of gas suppliers 10 arranged in parallel, and a body 61 supporting the gas suppliers 10. The supplier unit 52 is disposed such that, during use, all of the gas suppliers 10 except for their upper end portions are immersed in the wastewater W. The upper end portions may be sealed to immerse the entire supplier unit.

(Method of Fixing Supplier Unit 52)
Moreover, installing the gas suppliers 10 one by one in the wastewater treatment tank 51 takes time and increases installation costs. Therefore, a supplier unit 52 that holds multiple gas suppliers 10 in parallel may be manufactured, and one or more of the supplier units 52 may be installed inside the wastewater treatment tank 51. In this way, many gas suppliers 10 can be installed in the wastewater treatment tank 51 in a short time, so that the installation time and installation costs can be significantly reduced. The method of fixing the supplier unit shown in FIG. 6 will be described in detail below.

Since the supply unit 52 has multiple hollow gas supplies 10, when the supply unit 52 is installed in the wastewater treatment tank 51, a large buoyancy acts on the supply unit 52. Therefore, fixing brackets 63 and anti-floating members 62 are used to prevent the supply unit 52 from floating up.

The fixing brackets 63 fix the supply unit 52 to the bottom surface 515 of the wastewater treatment tank 51. The fixing brackets 63 are L-shaped steel members. The fixing brackets 63 are fixed to the bottom surface 515 of the wastewater treatment tank 51 and have a structure that extends vertically. The fixing brackets 63 fix, for example, four points at the four corners of the supply unit 52 to the bottom surface 515 of the wastewater treatment tank 51. This ensures that the supply unit 52 is fixed without swinging from side to side. The number of fixing brackets 63 is not limited to four, and any number is acceptable as long as the supply unit 52 is fixed.

The anti-floating member 62 fixes the supply 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 62a and a vertical plate 62b extending vertically from the base plate 62a. The base plate 62a is fixed to the upper part of the side walls 511-514 of the wastewater treatment tank 51 (see Figure 6). The vertical plate 62b holds down the supply unit 52 from above, preventing it from floating up.

The distance L1 (see Figs. 1, 3, 10, etc.) between the inner side walls 511-514 of the wastewater treatment tank 51 and the gas supplier 10 of the supplier unit 52 is preferably 5 mm or more and 1000 mm or less, more preferably 20 mm or more and 500 mm or less. If the distance from one side of the supplier unit is 5 mm or less, installation is difficult, and if it is 1000 mm or more, the contact efficiency between the wastewater and the side of the gas supplier 10 (or the microorganisms attached to the gas supplier) decreases, and there is a risk of a decrease in wastewater treatment performance. If it is 5 mm or more and 1000 mm or less, it is possible to prevent short circuit flow, and it is preferable in that it is easy to install the necessary piping components between the two supplier units 52, install an aeration tube, and handle the installation.

In this embodiment, as shown in Figures 1 to 3, one supplier unit 52 is disposed in one wastewater treatment tank 51. Multiple supplier units 52 may be disposed in one wastewater treatment tank 51. This case will be described in detail later in the second to fourth embodiments.

(Gas supplier 10)
Each gas supplier 10 is a structure that supplies gas supplied from the opening 21b into the wastewater W in a state where it is immersed in the wastewater W of the wastewater treatment tank 51. As shown in FIG. 4, the gas supplier 10 includes a gas delivery layer 12 and a gas permeable membrane 21. A part of the air delivery pipe 31 of the air delivery unit 30 is inserted into the internal space of the gas supplier 10 via the opening 21b. Gas (air, oxygen) is supplied from the air delivery unit 30 to the internal space of the gas supplier 10. In addition, a part of the liquid delivery pipe 41 of the liquid delivery unit 40 may be disposed in the internal space of the gas supplier 10. Condensed water generated in the gas delivery layer is discharged from the internal space of the gas supplier 10 to the outside via the liquid delivery unit 40. In this embodiment, the opening 21b allows air and gas to enter and exit the internal space of the gas supplier 10 in addition to the air delivery pipe 31 and the liquid delivery pipe 41. The opening 21b may be sealed so that air and gas cannot enter or leave the opening 21b other than through the air supply pipe 31 and the liquid supply pipe 41.

As shown in FIG. 2, each gas supply body 10 is a flat plate-shaped member and is arranged so that the surface is expanded along the vertical direction (depth direction) and the horizontal direction (horizontal direction). This ensures an efficient contact area with the wastewater W. In addition, by arranging each gas supply body 10 so that the side of each gas supply body 10 is parallel to the straight line connecting the inlet 51a and the outlet 51b, the wastewater W supplied from the inlet 51a to the wastewater treatment tank 51 flows smoothly toward the outlet 51b. The number of gas supplies 10 constituting the supply body unit 52 does not necessarily have to be multiple, and may be single. The gas supply body may also be spiral-shaped or hollow fiber-shaped. In the case of a spiral shape, a gas supply body is arranged inside as in the case of a flat plate, and an air supply section and a liquid supply section are inserted into the gas supply body. In the case of a hollow fiber shape, if the strength of the hollow fiber itself can hold the internal space, the gas supply body may not be required. The air supply section and liquid supply section are inserted inside the header, which bundles multiple hollow fibers.

If the spacing between the gas supply bodies 10 is defined as the spacing between the outer surfaces of two adjacent gas supply bodies 10, not including the thickness of the gas supply body 10, then the spacing between the gas supply bodies 10 is preferably 5 mm or more and 200 mm or less. If the spacing between the gas supply bodies 10 is less than 5 mm, clogging may occur due to microorganisms growing on the gas permeable membrane 21. If the spacing between the gas supply bodies 10 exceeds 200 mm, the efficiency of contact with the wastewater may decrease, making it difficult to improve the wastewater treatment performance. In order to reliably avoid the above problems, it is more preferable to set the spacing between the gas supply bodies 10 to 15 mm or more and 50 mm or less.

Figure 4 is a vertical cross-sectional view of the gas supply body 10. As shown in Figure 4, the gas supply body 10 includes a gas delivery layer 12 and a gas permeable membrane 21, and the gas delivery layer 12 is disposed in a bag formed by the gas permeable membrane 21. The bag is formed by overlapping two gas permeable membranes 21, 21 and bonding the three ends of these gas permeable membranes 21, 21, and has an opening 21b (see Figure 4) at the upper end (the end on the gas delivery side of the gas delivery layer 12). The gas delivery layer 12 is inserted into the bag through the opening 21b, so that the outer periphery of the gas delivery layer 12 is covered by the gas permeable membrane 21. The position or shape of the opening 21b is not limited, and for example, a part of each end (including the top side, bottom side, and horizontal side (vertical line) of the bag) may be an opening.

(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 36, a manifold 35, and an air supply pipe 31. The air supply pipe 31 is a pipe that supplies air (oxygen) sent from the blower 36 to the inside of the gas supplier 10. The manifold 35 is connected to the blower 36 at one end and to the multiple air supply pipes 31 at the other end. The air supply unit 30 may be partially 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 the manifold 35, the air supply pipe 31, or any of the piping paths connecting the members constituting the air supply unit 30. The material and shape of the part of the air supply unit 30 installed under the water surface are not limited, but a material with good thermal conductivity is preferable. The material of the air supply unit 30 may be metal or resin. The metal may be copper, aluminum, iron, or stainless steel.

The gas supplied to the wastewater W via the gas supply 10 is a gas containing oxygen to promote activation of aerobic microorganisms in the wastewater W. Specifically, it may be air or pure oxygen. In the illustrated example, gas is supplied from the blower 36 to the opening 21b. From the viewpoint of keeping manufacturing costs low, it is also possible to directly introduce atmospheric air into the gas supply 10 from the opening 21b without using the blower 36.

(Manifold 35)
As shown in Figs. 1 and 6, the manifold 35 is installed above the water surface of the treatment tank 51 in which the water W is stored. The manifold 35 is provided with an inlet 35a and an outlet 35b for the aeration gas. The material and shape of the manifold 35 are not limited, but a material with low thermal conductivity is preferable so as not to cause a significant difference between the temperature of the aeration air and the temperature of the wastewater. The material of the manifold 35 may be a resin or a metal, and the resin may be vinyl chloride or polyethylene. In addition, the manifold 35 may have a laminated structure having a heat insulating layer, and a coating material for heat insulation may be used for the outer layer.

In this embodiment, the inlet 35a and outlet 35b of the manifold 35 are always open. The supplied gas flows continuously or intermittently from the inlet 35a to the outlet 35b.

The shape of the manifold 35 is not particularly limited, and the ends may have a structure with connectivity, such as a flange or union. Multiple supply units 52 (purification units) may be connected via the connecting parts, and air may be simultaneously sent from one power unit to multiple supply units 52 (purification units).

The installation location of the manifold 35 is not particularly limited, and may be installed, for example, on a body 61 that bundles the gas supply bodies 10 as shown in FIG. 6. In this embodiment, the manifold 35 is fixed to the body 61 by a fixing jig. The fixing jig may be a metal fitting (U-bolt). The fixing jig may be a clamp.

The means for connecting the manifold 35 and the air supply pipe 31 is not particularly limited, and may be connected in a non-removable manner by fusion or adhesion, or may be connected in a simply removable manner by screwing. Also, a connection that includes both of these may be used.

(Gas-permeable membrane 21)
The gas-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). The gas-permeable membrane 21 is also called a waterproof air-permeable membrane. When the gas supplier 10 is immersed in the wastewater treatment tank 51, the gas-permeable membrane 21 has the property 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 gas-permeable membrane 21 to which air (oxygen) is continuously supplied, as shown in FIG. 7. Thus, microorganisms adhere to the surface 21a of the gas-permeable membrane 21, forming a biofilm 214. Then, due to the action of the microorganisms contained in the wastewater W or held on the surface 21a, the microscopic solid organic matter or nitrogen compounds dissolved or dispersed in the water are decomposed, and the wastewater is purified.

Specifically, as shown in FIG. 4, the gas-permeable membrane 21 includes a substrate 211, a gas-permeable non-porous layer 212, and a microorganism support layer 213. In the illustrated example, the gas-permeable membrane 21 is laminated in the order of the substrate 211, the gas-permeable non-porous layer 212, and the microorganism support layer 213. The microorganism support layer 213 is the outermost layer that contacts the wastewater W. Note that, unlike the illustrated example, the gas-permeable membrane 21 may be laminated in the order of the gas-permeable non-porous layer 212, the substrate 211, and the microorganism support layer 213.

(Substrate 211)
The substrate 211 is a microporous film formed from 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.

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 method, a melting recrystallization method, a powder sintering method, a foaming method, or a solvent extraction. The substrate 211 may also be a self-organized honeycomb microporous membrane.

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 Test Method 6.1 Thickness Measurement Method.

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 a pore diameter obtained by observing the surface with a scanning electron microscope (SEM) and determining the pore diameter from the observed image by the method described below. The observation magnification can be any magnification as long as the pore diameter of the object to be observed can be calculated appropriately.
(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.

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 x 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, a test temperature of room temperature (20°C ± 5°C), a wetting liquid of Galwick (surface tension 15.7 dynes/cm), a pressurized gas of compressed air, a sample diameter of 33 mm, a maximum supply pressure of 250 psi, and a differential pressure rise rate of 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.

(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 gas permeable. 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.

The gases that permeate the gas-permeable non-porous layer 212 include oxygen, carbon dioxide, nitrogen, hydrogen, alcohols such as methanol and ethanol, organic solvents, or 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 the method specified in JIS K 7126.

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 a resin that cures by exposure to ultraviolet light. It may also be a resin that cures by organic peroxide crosslinking, addition reaction crosslinking, or condensation crosslinking.

The material of the gas-permeable non-porous layer 212 may include a thermosetting polymer selected from polyolefin, polystyrene, polysulfone, polyethersulfone polytetrafluoroethylene, acrylic resin, polyurethane resin, and copolymers of these materials. In addition, 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 urethane resin and silicone resin.

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.).

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. The monomer used may be, for example, a monomer represented by the following chemical formula: _HSiCl3 , _SiCl4 , MeSiHCl2 _, Me3SiCl _{, MeSiCl3} , _Me2SiCl2 , Me2HSiCl, PhSiCl3 _, Ph2SiCl2 _{, MePhSiCl2 , Ph2MeSiCl} , CH2=CHSiCl3, Me(CH2=CH _{) SiCl2} , _Me2 ( _{CH2 =} CH) _SiCl , ( _{CF3CH2CH2)MeSiCl2, (CF3CH2CH2)SiCl3, CH18H37SiCl3 ( 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 _{kinds .} Other organic groups include alkyl groups such as propyl, isopropyl, butyl, isobutyl, tert-butyl, hexyl, octyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; and aralkyl groups such as benzyl, 2-phenylethyl, and 3-phenylpropyl. Among these, methyl, phenyl, or a combination of both is 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 using a polyorganosiloxane that has particularly good solvent resistance, it is preferable to further combine a methyl group, a phenyl group, or a combination of both with a 3,3,3-trifluoropropyl group. In addition, the silicone resin composition may contain an organoalkoxysilane. Examples of organoalkoxysilane include compounds represented by the following chemical formulas, and they 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 , C10H21Si (} OCH3) ₃ , PhSi( _OCH3 ) ₃ , Ph2Si( _OCH3 ) _{2 , MeSiOC2H5 , Me2Si ( OC2H5} ) ₂ , Si _{( OC2H5} ) ₄ , _{C2H5Si ( OC2H5 ) 3} , PhSi _{(OC2H5 ) 3 , Ph2} Si( _{OC2H5 ) 2} .

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 .

The reaction method for obtaining the silicone polymer used in the silicone resin may involve, for example, hydrolysis of chlorosilanes, ring-opening polymerization of cyclic dimethylsiloxane oligomers, etc. Examples of the polymers that can be used include dimethyl polymers, methylvinyl polymers, methylphenylvinyl polymers, and methylfluoroalkyl polymers.

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-CH ₃ ) or a vinylsilyl group (Si-CH═CH ₂ ) 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.

(Microorganism Support Layer 213)
The microorganism support layer 213 is a layer that holds microorganisms on its surface or inside, has a space inside where microorganisms can grow, and allows organic matter in water to pass through. Examples of the material of the microorganism support layer 213 include porous sheets such as mesh, woven fabric, nonwoven fabric, foam, or microporous membrane. Examples of the material of the porous sheet include 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, phenol resin, fluorine resin and polyvinyl butyral resin, polyimide, polyphenylene sulfide, para- and meta-aramid, polyarylate, carbon fiber, glass fiber, aluminum fiber, steel fiber, ceramic, etc. Considering the microbial adhesion and processability, polyolefin resin, polyester resin, polyamide resin, acrylic resin, polyurethane resin, and carbon fiber are preferred.

The basis weight of the microbial support layer 213 is preferably 2 g/m ² or more and 500 g/m ² or less, and more preferably 10 g/m ² or more and 200 g/m ² or less. The basis weight of the microbial support layer 213 is a value measured by mass per unit area according to JIS1913:2010 General Nonwoven Fabric Test Method 6.2. By having the basis weight of the microbial support layer 213 be 2 g/m ² or more, it is possible to obtain an effect that the surface is uneven, making it easier for microorganisms to be retained in the microbial support layer 213. In addition, by having the basis weight of the microbial support layer 213 be 500 g/m ² or less, a space in which microorganisms can grow is generated inside the microbial support layer 213, making it easier to retain microorganisms, and it is possible to obtain an effect that the space makes it easier to supply oxygen to the microorganisms.

The thickness of the microorganism support layer 213 is preferably 5 μm or more and 2000 μm or less, and more preferably 20 μm or more and 500 μm or less. The thickness of the microorganism support layer 213 is a value measured according to JIS 1913:2010 General Nonwoven Fabric Test Method 6.1 Thickness Measurement Method.
The microbial support layer 213 may be formed by surface treatment of the substrate 211. In this way, the surface treatment can increase the surface roughness and membrane potential of the substrate 211, improving the adhesion of microorganisms. For example, the surface treatment may involve graft polymerization of glycidyl methacrylate and further reaction with diethylamine or sodium sulfite. Alternatively, the surface treatment may involve graft polymerization of glycidyl methacrylate and then reaction with ammonia or ethylamine.

(Gas Delivery Layer 12)
5 is a perspective view showing the gas-delivery layer 12. The gas-delivery layer 12 is a hollow plate-like member made of paper, resin, or metal. The gas-delivery layer 12 is a structure having a gas flow path S that delivers gas supplied from a first end side along a first direction. Gas from the gas delivery unit 30 (air delivery tube 31, see FIG. 1) is supplied to the lower end of the gas-delivery layer 12 via the gas delivery unit 31a. The gas-delivery layer 12 has a gas flow path S that delivers the supplied gas in the first direction (see the dashed line in FIG. 5), and releases the gas from the gas passage hole 13 on the side surface.

More specifically, as shown in FIG. 5, the gas delivery layer 12 has multiple core materials 12a, a front liner 12b, and a back liner 12c. The front and back surfaces of the gas delivery layer 12 are composed of the front liner 12b and the back liner 12c, which are plate-shaped members.

The multiple core materials 12a each extend in a first direction and are arranged at a predetermined interval in a direction perpendicular to the first direction. By sandwiching the multiple core materials 12a between the front liner 12b and the rear liner 12c, multiple gas flow paths S partitioned by the core materials 12a are formed in the space between the front liner 12b and the rear liner 12c.

In addition, each core material 12a functions as a support portion that prevents the space between the front liner 12b and the back liner 12c from shrinking when pressed from the front liner 12b and back liner 12c sides. When the gas supplier 10 is immersed in wastewater W as shown in Figures 1 to 3, the core material 12a maintains the space between the front liner 12b and the back liner 12c so that the cross-sectional area of the gas flow path S does not shrink due to water pressure. This ensures a sufficient amount of gas delivery in the gas delivery layer 12 (gas flow path S).

The front liner 12b and the back liner 12c each have a plurality of gas passage holes 13. The gas passage holes 13 are through holes formed in the front liner 12b and the back liner 12c, and the gas passage holes 13 connect the gas flow path S and the gas permeable membrane 21, so that the gas flowing through the gas flow path S is supplied to the liquid via the gas permeable membrane 21.

For example, the gas passage holes 13 are formed when the gas delivery layer 12 is molded. Alternatively, the gas passage holes 13 may be formed by processing the front liner 12b and the back liner 12c after the gas delivery layer 12 is molded. A porous sheet may be used for the front liner and the back liner. Also, if sufficient gas supply performance is obtained, a porous sheet may be used for the gas delivery layer.

The materials that make up the gas delivery layer 12 include paper, ceramic, aluminum, iron, 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.

In addition, because of their superior strength, the materials for the gas delivery layer 12 are preferably paper, aluminum, iron, polyolefin resin, polystyrene resin, PVC resin, or polyester resin.

In order to keep material costs low, it is preferable to use materials such as paper, resins such as polyolefin, polystyrene, PVC, and polyester, and metals such as aluminum as the material for the gas delivery layer 12. In addition, the material cost for the gas delivery layer 12 can be kept low by using cardboard formed so that the gas flow path S extends in the first direction (see the dashed line in FIG. 5) as the gas delivery layer 12.

The hole shapes forming the gas permeable holes of the gas delivery layer 12 can be various shapes such as circular or polygonal (including honeycomb structure). There are no particular limitations on the hole shape, but polygonal shapes are preferred, and specifically rectangular or square shapes are preferred.

(Liquid sending section 40)
The liquid delivery unit 40 has a function of discharging a fluid, which is a liquid such as water and/or a gas such as air, from the internal space of the gas supplier 10 to the outside. The liquid delivery unit 40 has a liquid delivery tube 41, a manifold 45, and a suction pump 46. The liquid delivery tubes 41 are connected to the internal spaces of the gas suppliers, respectively. The manifold 45 is a tube having a structure in which multiple tubes branch off from one tube. The manifold 45 is connected to the multiple liquid delivery tubes 41 and the suction pump 46. The suction pump 46 is connected to the manifold 45. The suction pump 46 can suck either a liquid or a gas, or a gas-liquid mixed fluid. The manifold 45 of the liquid delivery unit 40 may also be fixed to the body 61 with a fixing jig, similar to the manifold 35 of the gas delivery unit 30. The fixing jig is a metal fitting. The metal fitting may be a U-bolt or a clamp.

The cross-sectional shape of the liquid supply pipe 41 is not particularly limited, and may be, for example, a circle, any polygon such as a rectangle, or a combination of a part of a circle and a part of a polygon, such as a D-shaped cross section. The cross-sectional area of the inner diameter is preferably 0.1 ^mm2 or more and ¹⁰⁰ mm2 or less, more preferably ^0.5 mm2 or more and ¹⁰ mm2 or less from the viewpoint of increasing the degree of freedom of the suction pump, and even more preferably 1 ^mm2 or more and ⁴ mm2 or less from the viewpoint of generating the necessary pressure loss with a small air flow rate and obtaining a sufficient drainage flow rate.

(Occurrence of Pressure Loss, Pressure Loss Generating Section 47)
The liquid feed pipe 41 has a function of generating a pressure loss. The liquid feed pipe 41 may generate a pressure loss by having a narrow flow path throughout the entire liquid feed pipe 41, or the liquid feed pipe 41 may have a pressure loss generating portion 47 as a portion where a particularly high pressure loss occurs.

The pressure loss generating portion 47 is a portion where a flow pressure loss occurs due to the flow of gas. The pressure loss generating portion 47 can be in various forms. The pressure loss generating portion 47 can be an orifice portion 47a, 47b (FIGS. 9A, 9B) in the liquid supply pipe, a narrowed portion 47c (FIG. 9C) in the liquid supply pipe 41, a curved portion 47d (FIG. 9D) in the liquid supply pipe 41, or a portion where a communicating porous member 47e (FIG. 9E) is disposed in the liquid supply pipe 41. The orifice portions 47a, 47b are shaped with a thin wall with holes inside the liquid supply pipe. A plate with holes may be installed inside the liquid supply pipe 41. The number of holes in the orifice portion may be one (FIG. 9A) or many (FIG. 9B).

(Operation of the liquid delivery unit)
In the wastewater treatment system 50 of this embodiment, condensed water is generated in the internal space of the gas supplier 10. If this condensed water is not removed, a part of the gas supply passage may be clogged, resulting in a decrease in gas supply efficiency.

8A and 8B show a part of the wastewater treatment system 50 of the present disclosure. That is, the gas supply bodies 10a and 10b and the liquid delivery section 40 are shown. FIG. 8A shows a state in which liquid (water) has accumulated in the internal space of the gas supply bodies 10a and 10b. The amount of water accumulated in the internal space of the gas supply bodies 10a and 10b is different as shown in FIG. 8A. In this case, the wastewater treatment system 50 of this embodiment uses the liquid delivery section 40 to drain the internal space of the gas supply bodies 10a and 10b. That is, the suction pump 46 is operated to create a negative pressure in the manifold 45, and liquid is drained from the gas supply bodies 10a and 10b.

In this way, when the liquid is continuously discharged by the liquid delivery unit 40, as shown in FIG. 8B, all liquid (water) is discharged from the gas supply 10b, which initially had a small amount of accumulated water. In this state, gas is discharged from the internal space of the gas supply 10a, and the flow of the gas (faster than the discharge of the liquid) generates a flow pressure loss. This pressure loss maintains the negative pressure in the manifold 45, and liquid continues to be discharged from the gas supply 10b, where liquid remains. Note that the capacity of the suction pump 46 and the structure of the liquid delivery unit 40 (adjustment of the generated pressure loss) are adjusted in advance at the design stage so that a negative pressure equal to or greater than the head pressure difference of the liquid is generated.

In this embodiment, the amount of gas supplied to the internal space of the gas supplier 10 by the air supply pipe 31 is preferably greater than the amount of gas exhausted by the liquid supply pipe 41. In this case, even when the suction pump 46 is operating, the pressure in the internal space of the gas supplier 10 is approximately atmospheric pressure. In addition, the wastewater treatment system 50 has a mechanism for preventing the pressure in the internal space of the gas supplier 10 from fluctuating significantly from atmospheric pressure. In this embodiment, the wastewater treatment system 50 preferably has a mechanism for exhausting the internal space of the gas supplier 10 (including exhausting from the opening 21b) in addition to the liquid supply pipe 41.

In the case where there are three or more gas supplies 10, the liquid is discharged in the same manner starting from the gas supply 10 that initially contained the smallest amount of accumulated water, until the entire water has been discharged.
In the wastewater treatment system 50 of the present embodiment, the pressure in the manifold 45 drops precisely because of the pressure loss generating unit 47. Without the pressure loss generating unit 47, in the state of Fig. 8B, air would be preferentially sucked from the gas supplier 10b from which the liquid has been discharged, the negative pressure in the manifold 45 would not be maintained, and liquid would not be able to be discharged from the gas supplier 10a in which liquid remains. In the present disclosure, by generating a pressure loss, even after the liquid discharge from the gas supplier 10b has been completed, the liquid can be continuously discharged from the other gas suppliers 10a.

(Baffle plate 65)
In the wastewater treatment system, a baffle plate 65 for blocking the flow of wastewater may be provided. At least one baffle plate 65 is disposed in the wastewater treatment tank 51, and the baffle plate is disposed in a vertical direction to the water surface, thereby blocking the wastewater flow path, and the contact time between the gas supplier 10 and the wastewater is extended. Furthermore, the baffle plate 65 is disposed so as to contact one side wall of the wastewater treatment tank 51, so that the wastewater flow path between the one side wall and the supplier unit 52 is blocked, and the effect is further enhanced. The baffle plate 65 may be disposed between the side wall 511 on which the wastewater inlet 51a is disposed and the supplier unit 52, or between the side wall 512 on which the wastewater outlet 51b is disposed and the supplier unit 52. The baffle plate 65 may be disposed between two supplier units 52. This case will be described in detail in the third and fourth embodiments below.

(Submerged Weir 80)
Also, a shielding portion may be provided to block the flow of wastewater flowing in from the wastewater inlet 51a. In this embodiment, as shown in Figs. 2 and 3, a submerged weir 80 may be provided near the wastewater inlet 51a as the above-mentioned shielding portion. The submerged weir 80 (shielding portion) is a plate material whose both side edges are supported by the side walls 513 and 514. The wastewater flowing in from the wastewater inlet 51a flows downward through the space between the submerged weir 80 (shielding portion) and the side wall 511, and passes between the lower end of the submerged weir 80 and the bottom surface 515. After this, the wastewater flows while gradually rising toward the side wall 512 side (the wastewater outlet 51b side). The structure of the submerged weir 80 (shielding portion) is not limited to the above-mentioned structure. For example, the submerged weir 80 may be supported by a member extending downward from the top surface, or may be supported by a member extending upward from the bottom surface 515. Alternatively, the submerged weir may be supported by a member extending horizontally from the sidewall 511 panel.

(Overflow weir 81)
In addition, the wastewater treatment device 100 of this embodiment may be provided with an overflow weir 81 near the wastewater outlet 51b, as shown in Figures 2 and 3. The overflow weir 81 has an L-shape in side view, and one end of the L-shape is supported by the side wall 512. By providing the overflow weir 81, among the wastewater flowing to the side wall 512 side (the wastewater outlet 51b side), the wastewater that has overflowed the other end of the L-shape of the overflow weir 81 flows out from the wastewater outlet 51b to the outside of the wastewater treatment tank 51. Note that the structure of the overflow weir 81 is not limited to the above structure, and may be various structures that allow the wastewater to overflow evenly and allow the overflowed wastewater to flow out from the wastewater outlet 51b.

When the above-mentioned supplier unit 52 is used, the BOD removal performance, effective dimensions, and spacing of the gas supplier 10 and the effective dimensions and number of supplier units 52 installed are appropriately set according to the effective volume of the wastewater treatment tank 51, so that the value obtained by multiplying the BOD removal performance AgBOD/ ^m2 /day of the gas permeable membrane 21 by the installation area ^Bm2 / ^m3 of the gas permeable membrane 21 is 0.5kgBOD/ ^m3 /day or more.

For example, when the effective volume of the wastewater treatment tank 51 is ²⁴ m3 (width 2 m × length 4 m × water depth 3 m), a gas supplier 10 is prepared with effective dimensions of 1.6 m × height 2.6 m × length 1.8 m, and with gas permeable membranes 21 with a BOD removal performance of 20 gBOD/ ^m2 /day installed on both the front and back sides. Then, a supplier unit 52 with effective dimensions of 1.7 m width × height 2.7 m × length 1.8 m is manufactured to hold the gas suppliers 10 at intervals of 30 mm, and two of these supplier units 52 are installed in the wastewater treatment tank 51. If done as described above, the surface area of gas permeable membrane 21 will be 998 ^m2 (1.6 m x 2.6 m x 1.8 m/0.03 m x 2 x 2), and the installation area B ^m2 / ^m3 of gas permeable membrane 21 per effective volume of the wastewater treatment tank will be 41 ^m2 / ^m3 (998 ^m2 /24 ^m3 ). Therefore, the value A x ^BgBODm3 / ^day obtained by multiplying the BOD removal performance of 20 gBOD/ ^m2 /day by the installation area of gas permeable membrane ²¹ of 41 m2/m3 is 820 gBOD/ ^m3 /day, which is 0.5 kgBOD/ ^m3 /day or more. The width of the supply unit 52, 1.7 m, corresponds to the width of the unit frame (main body 61), the height of the supply unit 52, 2.7 m, corresponds to the height of the unit frame (main body 61), and the length of the supply unit 52, 1.8 m, corresponds to the length of a straight line connecting the opposing corners of the unit frame (main body 61).

When the supplier unit 52 having N gas suppliers 10 is installed in the wastewater treatment tank 51, the installation area of the gas permeable membrane 21 is reduced by about 90% compared to when the N gas suppliers 10 are installed in the wastewater treatment tank 51 as they are. Therefore, when the supplier unit 52 is used, in order to obtain treatment performance equivalent to that of the activated sludge method, it is preferable that the installation area of the gas permeable membrane 21 per unit volume per effective volume of the wastewater treatment tank is 28 ^m2 / ^m3 or more. ^{28 m2} / ^m3 is a value obtained by calculating 25 ^m2 /m3/ ^0.9 .

Second Embodiment
In the first embodiment, one supplier unit 52 is disposed in one wastewater treatment tank 51. In the second embodiment, as shown in Fig. 10, four supplier units 52 are disposed in one wastewater treatment tank 51. The other configurations of the second embodiment are the same as those of the first embodiment.
10, of the four supplier units 52, two supplier units 52a and 52c are disposed adjacent to the side wall 511 where the inlet 51a is disposed, and two supplier units 52b and 52d are disposed adjacent to the side wall 512 where the outlet 51b is disposed. The gas supplier 10 in each of the supplier units 52a to 52d is disposed such that the longitudinal direction is along the side walls 513 and 514 in a plan view. In other words, the side surface of the gas supplier 10 is disposed approximately along the direction of the flow of the waste liquid.

The distance L2 between two adjacent supply units 52 is preferably 0 mm or more and 1000 mm or less. More preferably, it is 5 mm or more and 500 mm or less. The smaller the distance between two adjacent supply units 52, the less likely short-circuiting will occur. If the distance is within 1000 mm, the supply units 52 can be easily installed, which is preferable in terms of workability. In addition, for example, an aeration pipe for aeration may be installed between the two supply units 52. If the distance is 1000 mm or more, the contact efficiency between the wastewater and the side of the gas supply 10 (or microorganisms attached to the gas supply) decreases, and short-circuiting will occur, which may reduce the wastewater treatment performance.

As in the first embodiment, in the second embodiment, a shielding portion is provided to block the flow of wastewater flowing in from the wastewater inlet 51a. As the shielding portion, a submerged weir 80 is provided near the side wall 511 on which the wastewater inlet 51a is provided. The submerged weir 80 (shielding portion) is a plate material whose both side edges are supported by the side walls 513 and 514. The wastewater flowing in from the wastewater inlet 51a flows downward through the space between the submerged weir 80 (shielding portion) and the side wall 511, and passes between the lower end of the submerged weir 80 and the bottom surface 515. After this, the wastewater flows gradually upward toward the side wall 512 side (the wastewater outlet 51b side). The structure of the submerged weir 80 (shielding portion) is not limited to the above structure. For example, the submerged weir 80 may be supported by a member extending downward from the top surface, or may be supported by a member extending upward from the bottom surface 515. Alternatively, the submerged weir may be supported by a member extending horizontally from the sidewall 511 panel.

As in the first embodiment, in the second embodiment, an overflow weir 81 is provided near the side wall 512 on which the wastewater outlet 51b is provided. The overflow weir 81 is L-shaped in a side view, and one end of the L shape is supported by the side wall 512. By providing the overflow weir 81, the wastewater that flows to the side wall 512 side (the wastewater outlet 51b side) and overflows the other end of the L shape of the overflow weir 81 flows out from the wastewater outlet 51b to the outside of the wastewater treatment tank 51. Note that the structure of the overflow weir 81 is not limited to the above structure, and various structures that allow the wastewater to overflow evenly and allow the overflowed wastewater to flow out from the wastewater outlet 51b can be used.

Third Embodiment
A wastewater treatment device 100 of the third embodiment is shown in Fig. 11. In the wastewater treatment device 100 of this embodiment, a baffle plate 65 is disposed between the upstream supply units 52a, 52c and the downstream supply units 52b, 52d. The baffle plate 65 is disposed in a vertical direction to the water surface. One end of the baffle plate 65 contacts the side wall 514, and the other end extends toward the side wall 513. The other configurations of the wastewater treatment device 100 of this embodiment are exactly the same as those of the wastewater treatment device 100 of the second embodiment.

In the wastewater treatment device 100 of this embodiment, the baffle plate 65 is arranged vertically to the water surface in the wastewater treatment tank 51. This blocks the wastewater flow path, lengthening the contact time between the gas supplier 10 and the wastewater. Furthermore, in this embodiment, the baffle plate 65 is arranged in contact with the side wall 514 of the wastewater treatment tank 51. This blocks the wastewater flow path between the side wall 514 and the supplier unit 52, resulting in a greater effect.

Fourth Embodiment
The wastewater treatment device 100 of the fourth embodiment is shown in Fig. 12. In the wastewater treatment device 100 for the third embodiment gas, one baffle plate 65 is arranged between the upstream supply unit 52a, 52c and the downstream supply unit 52b, 52d. In contrast, in the wastewater treatment device 100 for the fourth embodiment gas, two baffle plates 65 are arranged between the upstream supply unit 52a, 52c and the downstream supply unit 52b, 52d. One end of one baffle plate 65 contacts the side wall 514, and the other end extends toward the side wall 513. One end of the other baffle plate 65 contacts the side wall 513, and the other end extends toward the side wall 514. The other configuration is exactly the same as that of the wastewater treatment device 100 of the third embodiment.

In the wastewater treatment device 100 of this embodiment, the wastewater flow path is blocked by two baffle plates 65 in the wastewater treatment tank 51, which increases the contact time between the gas supplier 10 and the wastewater. Furthermore, the baffle plates 65 are arranged in contact with the side wall 514 of the wastewater treatment tank 51, which blocks the wastewater flow path between the side wall 514 and the supplier unit 52, thereby further increasing the effect.

Fifth Embodiment
A wastewater treatment device 100 according to the fifth embodiment is shown in Fig. 13. In this embodiment, as shown in Fig. 13, the height of the inlet 51a from the ground (depth from the water surface) is higher than the height of the outlet 51b from the ground (depth from the water surface). The rest of the configuration of the wastewater treatment device 100 is exactly the same as that of the first embodiment.
In the wastewater treatment device 100 of this embodiment, the heights of the inlet 51a and the outlet 51b from the ground are different, so that the residence time of the wastewater W in the tank is increased. Also, short-circuiting of the wastewater W is prevented. The wastewater W can be brought into contact with the gas supplier 10 more efficiently, and the wastewater treatment performance is improved.

A plurality of inlets 51a and outlets 51b may be provided. By providing a plurality of inlets, the contact efficiency between the wastewater W and the gas supplier 10 is improved, which is more preferable. In addition, the plurality of inlets 51a may be disposed at the same height from the ground. The plurality of outlets 51b may be disposed at the same height from the ground.

In addition, in FIG. 13, the submerged weir 80 (shielding portion) and the overflow weir 81 are not drawn. In this embodiment, even if the submerged weir 80 (shielding portion) and the overflow weir 81 are not used, the effect of increasing the residence time of the wastewater W in the tank is still obtained. In this embodiment, the submerged weir 80 (shielding portion) and the overflow weir 81 may also be used as appropriate to further increase the effect of increasing the residence time of the wastewater W in the tank.

Sixth Embodiment
The wastewater treatment device 100 of the sixth embodiment is shown in Fig. 14. In this embodiment, as shown in Fig. 14, the height of the inlet 51a from the ground (depth from the water surface) is lower than the height of the outlet 51b from the ground (depth from the water surface). The rest of the configuration of the wastewater treatment device 100 is exactly the same as that of the first embodiment.
In the wastewater treatment device 100 of this embodiment, the heights of the inlet 51a and the outlet 51b from the ground are different, so that the residence time of the wastewater W in the tank is increased. Also, short-circuiting of the wastewater W is prevented. The wastewater W can be brought into contact with the gas supplier 10 more efficiently, and the wastewater treatment performance is improved.

A plurality of inlets 51a and outlets 51b may be provided. By providing a plurality of inlets, the contact efficiency between the wastewater W and the gas supplier 10 is improved, which is more preferable. In addition, the plurality of inlets 51a may be disposed at the same height from the ground. The plurality of outlets 51b may be disposed at the same height from the ground.

In addition, in FIG. 14, the submerged weir 80 (shielding portion) and the overflow weir 81 are not drawn. In this embodiment, even if the submerged weir 80 (shielding portion) and the overflow weir 81 are not used, the effect of increasing the residence time of the wastewater W in the tank is still obtained. In this embodiment, the submerged weir 80 (shielding portion) and the overflow weir 81 may also be used as appropriate to further increase the effect of increasing the residence time of the wastewater W in the tank.

Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the present disclosure as set forth in the claims.

10 Gas supplier 12 Gas supply layer 21 Gas permeable membrane 30 Air supply section 31 Air supply pipe 35 Manifold (of air supply section) 36 Air supply pump 40 Liquid supply section 41 Liquid supply pipe 45 Manifold (of liquid supply section) 46 Suction pump 47, 47a to 47e Pressure loss generating section 50 Wastewater treatment system 51 Wastewater treatment tank 51a (Wastewater) inlet 51b (Wastewater) outlet 511 to 514 (Wastewater treatment tank) side wall 515 (Wastewater treatment tank) bottom surface 52 Supplier unit 61 Body 62 Floating prevention member 62a Base plate 62b Vertical plate 54 Fixing jig 65 Baffle plate 80 Submerged weir (shielding section)
81 Overflow weir 100 Wastewater treatment device

Claims (7)

A wastewater treatment device that supplies oxygen that has permeated a gas-permeable membrane to wastewater stored in a wastewater treatment tank, thereby activating microorganisms in the wastewater and purifying the wastewater through the activity of the microorganisms,
A wastewater treatment tank having four side walls arranged on the four sides of a rectangle, the wastewater treatment tank having an inlet arranged on one side wall for introducing wastewater into the inside of the wastewater treatment tank, and an outlet arranged on a side wall opposite to the one side wall for discharging wastewater from the wastewater treatment tank;
A supply unit installed in the wastewater treatment tank, the supply unit including a plurality of gas supply bodies, each of the gas supply bodies having a gas permeable membrane and being a flat plate-shaped member, the plurality of gas supply bodies being arranged along a longitudinal direction in a plan view;
Equipped with
The distance between one of the four side walls of the wastewater treatment tank and the gas supplier adjacent to the side wall is 5 mm or more and 1000 mm or less.
Wastewater treatment equipment. Two or more supplier units are installed in one wastewater treatment device, and the interval between adjacent supplier units is 0 mm or more and 1000 mm or less.
The wastewater treatment device according to claim 1 . In the wastewater treatment tank, at least one of the inlets is disposed at a different height from the ground at the side wall than at least one of the outlets is disposed at a different height from the ground at the side wall.
The wastewater treatment device according to claim 1 . In the wastewater treatment tank, the interval between adjacent gas suppliers 10 is 5 mm or more and 200 mm or less.
The wastewater treatment device according to claim 1 . At least one baffle plate is disposed in the wastewater treatment tank to obstruct the flow of wastewater from the inlet to the outlet, and the baffle plate is disposed in a vertical direction with respect to the water surface.
The wastewater treatment device according to claim 1 . Two or more of the supplier units are installed in one wastewater treatment device, the baffle plate is installed between two of the supplier units, and the baffle plate is disposed in contact with one of four side walls of the wastewater treatment tank.
The wastewater treatment device according to claim 5. Within the wastewater treatment tank, a submerged weir for directing the flow of wastewater downward is installed near the side wall on which the inlet is installed, and within the wastewater treatment tank, an overflow weir for equalizing the flow of wastewater is installed near the side wall on which the outlet is installed.
The wastewater treatment device according to any one of claims 1 to 6.