JP7557413B2 - GAS SUPPLY, GAS SUPPLY UNIT, AND WASTEWATER TREATMENT APPARATUS - Google Patents

Description

This relates to a wastewater treatment device that utilizes the action of aerobic microorganisms to decompose organic matter in the water and purify the wastewater.

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.

Wastewater treatment equipment is being considered that treats wastewater by attaching microorganisms to a gas supply body that is permeable to gas but not to liquid. This equipment can reduce the pressure applied to the air supply, making it possible to reduce electricity costs. Examples of such gas supplies are disclosed in Patent Documents 1 and 2.

Patent No. 3743771 Patent No. 4680504

However, particularly with hollow fiber type MABR, there are cases where a high supply pressure is required to prevent the gas supply space from collapsing and becoming blocked due to water pressure, and cases where a high supply pressure is required due to pressure loss in the gas supply space. For this reason, compressors and blowers capable of supplying gas at high pressure are used, but they have the problem of high energy consumption. On the other hand, when the pressure loss in the gas supply space is reduced to reduce energy consumption, the volume of the gas supply space increases, and uniform oxygen supply to the entire gas supplier is not achieved, resulting in a problem of reduced treatment efficiency.

The gas supplier of the first aspect is used in a wastewater treatment device that purifies wastewater by utilizing the action of microorganisms,
a sheet laminate having an exterior immersed in wastewater and an interior supplied with gas;
a gas-transporting layer that divides the space inside the sheet stack;
an air supply unit disposed inside the sheet stack and supplying gas to a space inside the sheet stack;
Including,
The air supply unit includes:
a gas supply source unit that supplies gas from a gas supply source;
a distribution section that supplies the gas from the gas supply source section to a space divided by the gas supply layer;
and a throttle section between the distribution section and the gas delivery layer for restricting the gas supplied to the space divided by the gas delivery layer.

The gas supply of the second aspect is the gas supply of the first aspect, in which the gas is supplied from the bottom up within the space divided by the gas delivery layer.

The gas supply of the third aspect is the gas supply of the first or second aspect, and the distribution section has a minimum inner diameter (A) of 1 to 200 mm.

The gas supply body of the fourth aspect is the gas supply body of any one of the first to third aspects, and the constriction portion has a constriction width (B) of 0.01 to 8 mm.

The gas supply body of the fifth aspect is a gas supply body of any one of the first to fourth aspects, in which the ratio (B/A) of the minimum inner diameter part (A) of the distribution section to the narrowing width (B) of the narrowing section is 0.0001 or more and 0.6 or less.

A gas supplier of a sixth aspect is the gas supplier of any one of the first to fifth aspects, in which, under conditions in which gas is supplied to the entire gas supplier, the ratio (C/D) of the oxygen-containing gas supply rate (g/ ^m2 /day) per effective area of the gas supplier (C) to the pressure loss (kPa) (D) in the gas delivery layer is 210 or less.

The gas supply unit of the seventh aspect includes a plurality of gas supply bodies of any one of the first to sixth aspects.

The wastewater treatment device of the eighth aspect includes a gas supplier of any one of the first to sixth aspects, or a supplier unit of the seventh aspect.

The gas supplier, supplier unit, and device of the present invention can supply oxygen at low pressure, allowing it to be operated with little energy consumption.

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. 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 gas supply body 10 of a first embodiment. FIG. 1 is a perspective view showing a gas sending layer 12 constituting the gas supplier 10 of the first embodiment. FIG. This is a schematic diagram illustrating a microbial aggregate formed on the surface of the sheet laminate 21 of the gas supply body 10 immersed in wastewater in the wastewater treatment tank 51 of the wastewater treatment device 100 of the first embodiment, and the decomposition of at least one organic substance or nitrogen source by the microorganisms. 3 is a vertical cross-sectional view of the gas-sending layer 12 and the gas-sending section 60a of the first embodiment. FIG. FIG. 11 is a vertical cross-sectional view of the gas-sending layer 12 and the gas-sending section 60b of the second embodiment. 13 is a vertical cross-sectional view of the gas-sending layer 12 and the gas-sending section 60c of Comparative Example 1. FIG. 13 is a vertical cross-sectional view of the gas-sending layer 12 and the gas-sending section 60d of Comparative Example 2. FIG.

(Embodiment 1)
A sheet laminate according to a first embodiment of the present invention, a gas supplier including the sheet laminate, and a wastewater treatment device in which the gas supplier is disposed will be described with reference to the drawings.

Figure 1 is a vertical cross-sectional view showing a wastewater treatment device 100 according to a first embodiment of the present invention. Figure 2 is a horizontal cross-sectional view showing the wastewater treatment device 100. Figure 3 is a vertical cross-sectional view showing the wastewater treatment device 100, showing a cross section perpendicular to Figure 1.

(Wastewater treatment device 100)
The wastewater treatment device 100 of this embodiment utilizes the action of aerobic microorganisms contained in the wastewater W to decompose at least one organic matter or nitrogen source in the wastewater W, thereby purifying the wastewater W. As shown in Figures 1 to 3, the wastewater treatment device 100 includes a wastewater treatment tank 51, a supply unit 52, and a gas supply source 53 (see Figure 1).

(Wastewater treatment tank 51)
As shown in FIGS. 1 to 3, the wastewater treatment tank 51 is a bottomed container in which wastewater W is stored, and is provided with an inlet 51a and an outlet 51b on opposing side surfaces.

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 arrows in FIG. 3 indicate the flow of the wastewater W).

The volume of the wastewater treatment tank 51 is not particularly limited, but may be, for example, from 1 ^m3 to 10,000 ^m3 .

(Supplier unit 52)
1, the supplier unit 52 is a unitized gas supplier 10, and is disposed inside the wastewater treatment tank 51. In the illustrated example, the supplier unit 52 is composed of a plurality of gas suppliers 10 arranged in parallel. The supplier unit 52 is disposed such that, when in use, all of the gas suppliers 10 except for their upper end portions are immersed in the wastewater W.

(Gas supplier 10)
Each gas supplier 10 constituting the supplier unit 52 is a structure that supplies gas supplied from a gas supply source 53 to the wastewater W in a state where it is immersed in the wastewater W of the wastewater treatment tank 51. The gas supplied to the wastewater W through the gas supplier 10 is preferably a gas containing oxygen in order to promote activation of aerobic microorganisms in the wastewater W. Specifically, it may be air or pure oxygen. In the illustrated example, the gas from the gas supply source 53 is supplied to the opening 21b, and an air supply device or the like may be used as the gas supply source 53. From the viewpoint of keeping manufacturing costs low, the gas supply source 53 may not be used and the air in the atmosphere may be directly introduced into the gas supplier 10 from the opening 21b.

2 and 3, each gas supply 10 is a flat plate-like member and is arranged so that its surface extends in the vertical direction (depth direction) and the horizontal direction (horizontal direction). This ensures an efficient contact area with the wastewater W. Also, by arranging each gas supply 10 so that its side is parallel to the straight line connecting the inlet 51a and the outlet 51b, the wastewater W supplied from the inlet 51a into the wastewater treatment tank 51 flows smoothly toward the outlet 51b. The number of gas supplies 10 constituting the supply unit 52 does not necessarily have to be multiple, and may be single.

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 sheet laminate 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 shows a vertical cross-sectional view of the gas supply body 10, and a vertical cross-sectional view rotated 90° is shown in Figure 3. The gas supply body 10 comprises a sheet stack 21, a gas delivery layer 12, and an air delivery section 60. The sheet stack 21 has an exterior immersed in wastewater, and gas is delivered to the interior. The gas delivery layer 12 is disposed inside the sheet stack 21 and divides the internal space. The air delivery section 60 is disposed inside the bag of the sheet stack 21. The air delivery section 60 delivers gas supplied from a gas supply source 53 to the internal space of the sheet stack 21 (gas delivery layer 12).

The gas delivery layer 12 and the gas delivery section 60 are arranged in a bag formed by the sheet laminate 21. The bag is made by overlapping two sheet laminates 21, 21 and gluing the three ends of these sheet laminates 21, 21, and has an opening 21b (see FIG. 4) at the upper end (the end on the gas supply side of the gas delivery layer 12). The gas delivery layer 12 and the gas delivery section 60 are inserted into the bag through the opening 21b, so that the gas delivery layer 12 and the gas delivery section 60 are covered by the sheet laminate 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 60)
The gas sending section 60 supplies the gas supplied from the gas supply source 53 to the space inside the sheet laminate 21 (the gas sending layer 12). As shown in Figs. 3 and 4, the gas sending section 60 has an air sending source section 61, a distribution section 62, and a throttle section 63.

The air supply source 61 is disposed vertically on the side of the sheet stack 21 and the gas delivery layer 12 inside the bag of the sheet stack 21. The air supply source 61 supplies gas from the gas supply source 53 to the distribution section 62. The air supply source 61 may be an air supply pipe. The number and diameter of the air supply pipes are not particularly limited, but a diameter of 200 mm or less is preferable to ensure spacing between the gas suppliers 10. In addition, the number and diameter of the air supply pipes are preferably set so that the pressure loss for the gas flow rate is 5 kPa or less.

The distribution unit 62 is connected to the tip of the gas supply source unit 61. The distribution unit 62 is disposed inside the bag formed by the sheet stack 21, below the gas supply layer 12, in the gap between the gas supply layer 12 and the sheet stack 21. In other words, the distribution unit 62 is disposed approximately horizontally. The distribution unit 62 supplies the gas sent from the gas supply source unit 61 to the space divided by the gas supply layer 12.

The throttle section 63 is disposed between the distribution section 62 and the gas delivery layer 12. The throttle section 63 restricts the air supplied from the distribution section 62 to the space divided by the gas delivery layer 12.

In this embodiment, the gas from the gas supply source 53 flows from top to bottom through the gas supply section 61. It then flows horizontally through the distribution section 62 at the bottom of the bag of the sheet laminate 21. It then flows from the distribution section 62 through the throttle section 63, from bottom to top through the space divided by the gas delivery layer 12, in the direction of the gas flow path S. The gas flowing through the gas flow path S passes through the gas delivery layer 12 from the gas passage hole 13 on the side of the gas delivery layer 12, and is supplied to the microorganisms in the waste liquid.

The distribution section 62 preferably has a diameter of 1 mm or more in order to distribute air evenly, and 200 mm or less in order to ensure sufficient spacing between the gas supplies 10. A diameter of 30 mm or less is more preferable.

It is desirable that the narrowing width B of the narrowing section 63 is 0.01 mm or more from the viewpoint of dimensional stability, and 8 mm or less from the viewpoint of uniformly supplying gas to the gas flow path S. The distribution section 62 and the narrowing section 63 may have an integral structure. The narrowing section 63 may be configured integrally with the gas delivery layer 12.

In the above, the case where the distribution section 62 and the throttle section 63 are disposed inside and at the bottom of the bag of the sheet laminate 21 has been described, but the present disclosure is not limited to this. It is sufficient that the gas supplier 10 includes a distribution section 62 and a throttle section 63, the distribution section 62 distributes gas to the space divided by the gas delivery layer 12, and the throttle section 63 restricts the gas flowing from the distribution section to the space divided by the gas delivery layer 12. Modified examples include the following forms.

In this modified example, the gas supply source 61 supplies gas from the gas supply source 53 to the upper part of the gas delivery layer 12. The distribution section 62 and the throttle section 63 are arranged almost horizontally on the upper side of the gas delivery layer 12. The gas that has passed through the distribution section 62 and the throttle section 63 flows from top to bottom in each space divided by the gas delivery layer 12. The gas then passes through the gas delivery layer 12 from the gas passage hole 13 on the side of the gas delivery layer 12 and is supplied to the microorganisms in the waste liquid.

(Gas Delivery Layer 12)
5 is a perspective view showing the gas-sending layer 12. The gas-sending layer 12 is a hollow plate-like member made of paper, resin, or metal. The gas-sending layer 12 is a structure having a gas flow path S that sends out gas supplied from a first end side along a first direction.

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 section 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 to the sheet stack 21, so that the gas flowing through the gas flow path S is supplied to the liquid via the sheet stack 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.

From the viewpoint of keeping material costs low, it is preferable to use, for example, paper, resins such as polyolefin, polystyrene, PVC, and polyester, and metals such as aluminum as the material for the gas delivery layer 12. Also, the material cost for the gas delivery layer 12 can be kept low by using, as the gas delivery layer 12, cardboard formed so that the gas flow path S extends in the first direction (see the two-dot chain line in FIG. 5).

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.

In order to maintain the activity of the aerobic microorganisms, it is preferable to maintain the oxygen concentration inside the gas delivery layer 12. One method for this is to supply a predetermined amount of pure oxygen to maintain a constant oxygen concentration. One possible method for supplying the pure oxygen is, for example, powered air supply.

The length of the gas flow path S formed in the gas delivery layer 12 in the vertical direction (depth direction when immersed) may be, for example, 0.2 m or more, preferably 0.8 m or more, or 3.7 m or more. The length may be, for example, 6 m or less, preferably 4 m or less. The length of the gas flow path S in the horizontal direction perpendicular to the vertical direction may be, for example, 0.2 m or more, preferably 0.4 m or more, or, for example, 3.6 m or less, preferably 1.8 m or less.

Here, it is preferable that the vertical length of the gas flow path S is equal to or greater than the above-mentioned lower limit value, since this makes it easier to maintain the gas flow path S and ventilate the gas flow path S, thereby improving the wastewater treatment capacity, and it is preferable that the vertical length is equal to or less than the above-mentioned upper limit value, since this makes it easier to obtain the effect of improving the wastewater treatment capacity by ventilating the gas flow path S, and it is easier to install.

In addition, it is preferable for the lateral length of the gas flow path S to be equal to or greater than the above-mentioned lower limit in order to efficiently secure the contact area with the wastewater W and improve the efficiency of wastewater treatment, and it is preferable for the lateral length of the gas flow path S to be equal to or less than the above-mentioned upper limit in order to facilitate maintaining the strength of the entire gas supplier 10 and to facilitate the installation of the supplier unit 52.

The ratio of the length Lw of contact with the wastewater W to the length Ls of the gas flow path S may be, for example, 80% or more and 95% or less (see FIG. 1 for lengths Ls and Lw). It is preferable that the ratio of the length Lw of contact with the wastewater W to the length Ls is equal to or more than the lower limit value, in order to ensure a good amount of oxygen supplied from the gas flow path S and improve the efficiency of wastewater treatment. It is preferable that the ratio of the length Lw of contact with the wastewater W to the length Ls is equal to or less than the upper limit value, in order to prevent the wastewater W from entering the gas flow path S.

Alternatively, in order to prevent the wastewater W from entering the gas flow path S, the water contact length Lw may be set so that the water surface of the wastewater W is 2 cm or more away from the opening 21b of the gas supply body 10 (sheet laminate 21).

(Sheet laminate 21)
The sheet laminate 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 pass outward, thereby supplying oxygen into the liquid (wastewater). When the gas supplier 10 is immersed in the wastewater treatment tank 51, the sheet laminate 21 has the property of allowing air to pass from the inside (gas-sending layer 12) to the outside (wastewater W) and not allowing wastewater to pass 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 sheet laminate 21 to which air (oxygen) is continuously supplied, as shown in FIG. 6. Thus, microorganisms attach to the surface 21a of the sheet laminate 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 sheet laminate 21 includes a substrate 211, a gas-permeable non-porous layer 212, and a microorganism support layer 213. In the illustrated example, the sheet laminate 21 is laminated in the order of the microorganism support layer 213, the substrate 211, and the gas-permeable non-porous layer 212, and the substrate 211 is covered with the gas-permeable non-porous layer 212, and the outermost layer that contacts the wastewater W is composed of the microorganism support layer 213. Unlike the illustrated example, the sheet laminate 21 may be laminated in the order of the substrate 211, the gas-permeable non-porous layer 212, and the microorganism support layer 213 (opposite to the illustrated example, the substrate 211 may be located inside the gas-permeable non-porous layer 212). Even in this way, the substrate 211 can be covered with the gas-permeable non-porous layer 212, and the outermost layer that contacts the wastewater W can be composed of the microorganism support layer 213.

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

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 um to 500 um, and more preferably 50 um to 200 um. 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 um to 50 um from the viewpoint of preventing defects in the gas-permeable non-porous layer, and more preferably 0.1 um to 30 um 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 dry sample. By gradually increasing the pressure within a specified 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 pressure difference between the atmospheric pressure and the gas pressure at point X (Pa). 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), wetting liquid of Galwick (surface tension 15.7 dynes/cm), pressurized gas of compressed air, a diameter of the sample used of 33 mm, a maximum supply pressure of 250 psi, and a rate of increase of the differential pressure 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 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, 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 , _C10H21S i(OCH3) ₃ , PhSi( _OCH3 ) ₃ , _Ph2Si ( _OCH3 ) ₂ , _{MeSiOC2H5 , Me2Si ( OC2H5 )2 , Si ( OC2H5)4 , C2H5Si ( OC2H5 ) 3 ,} PhSi(OC ₂ H _{5 ) 3} , _Ph2Si ( _{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.

(Dehydration condensation reaction between silanol groups)
As the catalyst, zinc octylate, iron octylate, or an organic acid salt of cobalt, tin, or the like, or an amine catalyst may be used, and the reaction may be carried out by heating.

(Condensation reaction between silanol groups and hydrolyzable groups)
As a catalyst, an acid, an alkali, an organic tin compound, an organic titanium compound, etc. may be added. As a hydrolyzable group, an alkoxy group, an acetoxy group, an oxime group, an aminoxy group, a propenoxy group, etc. may be used.

(Reaction of methylsilyl and vinylsilyl groups with organic peroxides)
As a peroxide curing agent that accelerates the reaction, an organic peroxide, an acyl-based organic peroxide, an alkyl-based organic peroxide, or the like may be added. As an acyl-based organic peroxide, for example, p-methylbenzoyl peroxide may be used. As an alkyl-based organic peroxide, for example, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, dicumyl peroxide, or the like may be used. The reaction temperature is, for example, 120° C. or higher, and secondary vulcanization (post-cure) may be performed. The amount of peroxide curing agent added is preferably 0.1 to 10% by mass based on the solid content of the resin.

(Addition reaction of alkenyl group with hydrosilyl group)
As the alkenyl group, for example, a vinyl group is preferably used. The reaction temperature may be room temperature or may be heated. The reaction may be carried out in an open system or a closed system. In the process of obtaining a composition used in the addition reaction of an alkenyl group with a hydrosilyl group, an organic compound containing nitrogen, phosphorus, sulfur, etc., an ionic compound of a metal such as tin or lead, a compound having an unsaturated group such as acetylene, an additive for removing alcohol, water, or carboxylic acid may be added or a process of removing the additive may be used.

When using an addition reaction between an alkenyl group and a hydrosilyl group, polysiloxanes or hydrogen polysiloxanes having vinyl groups are preferably used.

The polysiloxane having a vinyl group is preferably a linear polysiloxane having a viscosity of 1 to 100,000 mPa·s at 23° C. The polysiloxane contains one or more vinyl groups per molecule. Specific examples of polysiloxanes having vinyl groups include dimethylsiloxane-methylvinylsiloxane copolymers capped with trimethylsiloxy groups at both molecular chain ends, methylvinylpolysiloxane capped with trimethylsiloxy groups at both molecular chain ends, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers capped with trimethylsiloxy groups at both molecular chain ends, dimethylpolysiloxane capped with dimethylvinylsiloxy groups at both molecular chain ends, methylvinylpolysiloxane capped with dimethylvinylsiloxy groups at both molecular chain ends, dimethylsiloxane-methylvinylsiloxane copolymers capped with dimethylvinylsiloxy groups at both molecular chain ends, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers capped with dimethylvinylsiloxy groups at both molecular chain ends, and dimethylpolysiloxane capped with trivinylsiloxy groups at both molecular chain ends. These polysiloxanes may be used alone or in combination of two or more.

The hydrogen polysiloxane preferably used is a linear polysiloxane with a viscosity of 1 to 100,000 mPa·s at 23°C. Hydrogen polysiloxane contains one or more hydrogen atoms bonded to silicon atoms in each molecule. Specific examples of hydrogen polysiloxanes include dimethylpolysiloxanes capped at both molecular chain terminals with dimethylhydrogensiloxy groups, dimethylpolysiloxanes capped at both molecular chain terminals with diphenylhydrogensiloxy groups, methylphenylpolysiloxanes capped at both molecular chain terminals with dimethylhydrogensiloxy groups, diphenylpolysiloxanes capped at both molecular chain terminals with dimethylhydrogensiloxy groups, methylphenylsiloxane-dimethylsiloxane copolymers capped at both molecular chain terminals with dimethylhydrogensiloxy groups, diphenylsiloxane-dimethylsiloxane copolymers capped at both molecular chain terminals with dimethylhydrogensiloxy groups, and mixtures of two or more of these, so long as the viscosity at 23°C is 1 to 100,000 mPa·s.

In the resin composition used in the addition reaction between alkenyl groups and hydrosilyl groups, the molar ratio of hydrogen atoms bonded to silicon atoms to alkenyl groups is preferably 0.01 to 20 moles, and more preferably 1 to 2 moles.

Examples of reaction catalysts that can be used include platinum group metals such as platinum, palladium, and rhodium, platinum compounds such as chloroplatinic acid, alcohol-modified chloroplatinic acid, and coordination compounds of chloroplatinic acid with olefins, vinylsiloxane, or acetylene compounds, and platinum group metal compounds such as tetrakis(triphenylphosphine)palladium and chlorotris(triphenylphosphine)rhodium. In addition, since compatibility with silicone oil is required, platinum compounds in which chloroplatinic acid is silicone-modified are preferably used. When using a catalyst, the amount of addition calculated from the solid content mass is preferably 0.01 ppm to 10,000 ppm, and more preferably 0.1 ppm to 1,000 ppm.

The total amount of hydrosilyl groups is usually 0.01 to 20 moles, and preferably 0.1 to 10 moles, per mole of alkenyl groups bonded to silicon atoms in the entire silicone resin composition. If the total amount is less than the lower limit of the above range, the resulting silicone resin composition tends to be difficult to cure sufficiently, and if it exceeds the upper limit of the above range, the mechanical properties and heat resistance of the cured product of the resulting silicone resin composition tend to be easily degraded.

Reaction control agents are added to silicone resins when they are mixed or when they are applied to a substrate, in order to prevent thickening or gelling before curing. Examples of reaction control agents that can be used include low molecular weight polysiloxanes with multiple alkenyl groups and acetylene alcohol-based compounds.

(Reaction caused by ultraviolet light)
Examples of ultraviolet-curable silicone resins that can be used include radical reaction types (acrylic and mercapto types), combined radical reaction/condensation reaction types (mercapto/isopropenoxy and acrylic/alkoxy types), and addition reaction types that use an ultraviolet-activated platinum catalyst.

In the acrylic radical reaction type, an organic group having an acrylic group bonded to a siloxane undergoes a radical polymerization reaction in the presence of a photosensitizer.

In the mercapto radical reaction type, an organic group having a mercapto group bonded to a siloxane and a polysiloxane having a vinyl group are subjected to a radical addition reaction in the presence of a photosensitizer.

Addition reaction types that use ultraviolet-active platinum catalysts include (methylcyclopentadienyl)trimethylplatinum complex and bisacetylacetonatoplatinum(II) complex, and are best cured with a light source centered around 365 nm.

The main functional groups used in the photocuring reaction may be acrylic or epoxy groups. A photoinitiator may be used in the composition used in the reaction with ultraviolet light.

(Method of imparting tackiness (adhesiveness) to silicone resin)
As a method for imparting tackiness (adhesiveness) to a silicone resin, for example, a method of adding a silicone polymer that imparts tackiness is preferably used. As a silicone polymer that imparts tackiness, for example, an MQ resin is preferably used. The MQ resin is a polymer having a three-dimensional structure synthesized from a monofunctional monomer (M unit) and a tetrafunctional monomer (Q unit). The molecular weight of the polymer having the three-dimensional structure is preferably 10 to 100,000, more preferably 100 to 10,000. As the organic group of the monomer of each functional group, a methyl group is preferably used, but in the case of an addition reaction type silicone resin, an alkenyl group is preferably used. The content of the MQ resin relative to the silicone resin is preferably 10 to 99% by mass, more preferably 20 to 80% by mass, calculated as a solid content, from the viewpoint of achieving both strength and tackiness of the silicone resin. In the present invention, when obtaining a silicone polymer that imparts adhesiveness, a difunctional monomer (D unit) or a trifunctional monomer (T unit) may be added as appropriate, or a monomer or oligomer having other functional groups may be added.

The MQ resin preferably has a structure in which the ends of the condensation product of Q units are blocked with M units. From the viewpoint of achieving both adhesion and strength of the silicone resin, the molar ratio of M units to Q units is preferably 0.4 to 1.2, and more preferably 0.6 to 0.9.

Additives may be added in the process of obtaining silicone polymers and silicone-based resins from silicone monomers. Examples of additives include reinforcing agents (silica fillers such as dry silica and wet silica), dispersants, adhesion aids (silane coupling agents, etc.), adhesion promoters (organometallic compounds, etc.), reaction control agents, extenders (crystalline silica, calcium carbonate, talc, etc.), heat resistance improvers (iron oxide, cerium oxide, titanium oxide, etc.), flame retardants (titanium oxide, carbon, etc.), thermally conductive fillers, conductive agents, surface treatment agents, pigments, dyes, or metal oxides, hydroxides, carbonates, and fatty acid salts of rare earths, titanium, zircon, manganese, iron, cobalt, nickel, etc.

As the silica filler, for example, a known fine powder silica can be used. The fine powder silica may be hydrophilic or hydrophobic. Examples of the hydrophilic fine powder silica include wet silica such as precipitated silica, and dry silica such as silica xerogel and fumed silica. Examples of the hydrophobic fine powder silica include fine powder silica obtained by hydrophobizing the surface of hydrophilic fine powder silica. Examples of the hydrophobizing agent include organosilazanes such as hexamethyldisilazane; halogenated silanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane; and organoalkoxysilanes in which the halogen atom of the halogenated silane is substituted with an alkoxy group such as a methoxy group or an ethoxy group. Examples of the hydrophobizing method include a method in which hydrophilic fine powder silica is heated with a hydrophobizing agent at 150 to 200 ° C, particularly at 150 to 180 ° C, for about 2 to 4 hours. The hydrophobic fine powder silica obtained by previously hydrophobizing the surface of the hydrophilic fine powder silica in this way may be blended into the adhesive of the present invention, or a hydrophobizing agent may be blended into the adhesive of the present invention together with the hydrophilic fine powder silica, so that the surface of the hydrophilic fine powder silica is hydrophobized at the stage of preparing the adhesive of the present invention.

Specific examples of silica fillers include hydrophilic finely powdered silica such as Aerosil (registered trademark) 50, 130, 200 and 300 (trade names, manufactured by Nippon Aerosil Co., Ltd.), Cabosil (registered trademark) MS-5 and MS-7 (trade names, manufactured by Cabot Corporation), Reolosil QS-102 and 103 (trade names, manufactured by Tokuyama Corporation), and Nipsil LP (trade name, manufactured by Nippon Silica Co., Ltd.); and hydrophobic finely powdered silica such as Aerosil (registered trademark) R-812, R-812S, R-972 and R-974 (trade names, manufactured by Degussa Co., Ltd.), Reolosil MT-10 (trade name, manufactured by Tokuyama Corporation), and Nipsil SS series (trade names, manufactured by Nippon Silica Co., Ltd.).

When finely powdered silica is used, the blending amount is usually 1 to 50 mass % converted to solid content. If the blending amount is less than 1 mass %, the strength imparting effect of the silica filler is likely to be insufficient, and if it exceeds 50 mass %, the resulting silicone resin composition is likely to be significantly lacking in fluidity and have poor workability.

As the adhesion promoter, for example, an organic titanium compound, such as an organic acid salt of titanium, can be used. The adhesion promoter can be used as a catalyst to further accelerate the curing of the silicone resin composition and further improve its adhesiveness. The adhesion promoter may be used alone or in combination of two or more kinds.

Examples of adhesion promoters include titanium chelate compounds, alkoxy titanium, or combinations thereof. Specific examples of titanium chelate compounds include diisopropoxybis(acetylacetonato)titanium, diisopropoxybis(ethylacetoacetato)titanium, dibutoxybis(methylacetoacetato)titanium, and the like. Specific examples of alkoxy titanium include tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, and the like. The alkoxy group in the alkoxy titanium may be linear or branched.

The amount of adhesion promoter is preferably 0.01 to 10 mass % in terms of solid content, and more preferably 0.1 to 5 mass %. If the amount is less than the lower limit of the range, the adhesiveness improving effect may not be easily achieved, and if the amount is more than the upper limit of the range, the surface curing of the resulting adhesive may be too rapid.

A silane coupling agent is a compound that has an alkoxy group bonded to a silicon atom and a reactive group that chemically bonds with an adherend such as a metal or various synthetic resins in one molecule, and a compound having an alkenyl group or a hydrogen atom may be used instead of the alkoxy group bonded to the silicon atom. An epoxy group or an acrylic group may be used as the reactive group that chemically bonds with the adherend.

When applying a silicone resin, a primer may be applied to the substrate before application. The primer may be a silicone resin of a condensation curing type or an addition curing type. The amount of primer applied is preferably 0.1 to 1.2 g/ ^m2 .

Examples of silicone resins include "SYLGRAD186", "DOWSIL3-6512", "SYLGRAD527", "DOWSILX3-6211", "SYLGRAD3-6636", "DOWSIL SE1880", "DOWSIL SE960", "DOWSIL781 Acetoxy Silicone", "DOW CORNING SE9187", "DOWSIL Q1-4010", "SYLGRAD 1-4128", "DOWSIL 3140 RTV Coating", "DOWSIL HC2100", and "SIL-OFF". Q2-7785", "Silaseal 3FW", "Silaseal DC738RTV", "DC3145", and "DC3140" (all manufactured by Dow Corning Corporation), "ELASTOSIL RT707W", "ELASTOSIL EL4300", "ELASTOSIL M4400", "ELASTOSIL M8012", "SILRES BS CREME C", "SILRES BS 1001", "SILRES BS 290", "ELASTSIL 912", "ELASTSIL E43N", "ELASTOSIL N9111", "ELASTOSIL N199", "SEMICOSIL 987GR", "ELASTOSIL RT772", "ELASTOSIL RT745", "ELASTOSIL LR3003/05", "ELASTOSIL LR3343/40", "ELASTOSIL LR3370/40", "ELASTOSIL LR3374/50BR", "ELASTOSIL EL1301", "ELASTOSIL EL 4406", "ELA STOSIL EL3530", "ELASTOSIL EL 7152", "ELASTOSIL R401/10OH", "SILPUREN 21XX series" (manufactured by Wacker Asahi Kasei Silicone Co., Ltd.), "KE-3423", "KE-347", "KE-3479", "KE-1830", "KE-1820", "KE-1056", "KE-1800T", "KE-66", "KE-1031", "KE-12", "KE-1300T", "SD4584PSA", "KS-847T", "KF-2005", "KNS-3002", "KR-100", "KR-101-10", "KR-130", "KR-3600", "KR-3704", "KR-3700", "KR- 3701", "X-40-3237", "X-40-3291-1", "X-40-3240", "Sealant 45", "Sealant Master 300", "Sealant 72", "KE-42", "Sealant 70", "KE-931-U", "KE-9511-U", "KE-541-U", "KE-153-U", "KE-361-U", "KE-1950-10", "KEG-2000-40", "KE-2019-40", "KE-2090-50", "KE-2096-60" (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be used. A catalyst may be further added to the silicone-based resin. As the catalyst, organic acid salts such as zinc octylate, iron octylate, cobalt, and tin, and amine-based catalysts can be used. In addition, organic tin compounds, organic titanium compounds, and platinum compounds can also be used. Examples of catalysts that can be used include "CAT-PL-50T" (manufactured by Shin-Etsu Chemical Co., Ltd.) and "NC-25" (manufactured by Dow Corning Toray Co., Ltd.). In addition, solvents such as toluene, xylene, or alcohols may be added during application. Examples of primers that can be used include "Primer AQ-1", "Primer C", "Primer MT", "Primer T", "Primer D", "Primer A-10", "Primer R-3", and "Primer A-20" (manufactured by Shin-Etsu Chemical Co., Ltd.).

The method for forming the gas-permeable non-porous layer is not particularly limited, and the gas-permeable non-porous layer can be produced by laminating the gas-permeable non-porous layer on the porous substrate using a reverse roll coater, a forward rotation roll coater, a gravure coater, a knife coater, a rod coater, a slot orifice coater, an air doctor coater, a kiss coater, a blade coater, a cast coater, a spray coater, a spin coater, an extrusion coater, a hot melt coater, or the like. The gas-permeable non-porous layer can also be produced by a method such as powder coating or electrochemical coating. The substrate may be coated by immersing it in the raw material liquid for the gas-permeable non-porous layer. The substrate may be in the form of a sheet or a hollow fiber. In a step prior to coating, a pretreatment such as primer coating or corona treatment may be performed.

The basis weight of the gas permeable nonporous layer 212 is preferably 10 g/m2 or ^more and 500 g/m2 ^or less, and more preferably 20 g/m2 or ^more and 200 g/m2 or ^less . The basis weight of the gas permeable nonporous layer 212 is determined by the following relational formula (1) as the difference D (g/ ^m2 ) between the basis weight E (g/m2) of the substrate before the gas permeable nonporous layer 212 is laminated and the basis weight F (g/ ^m2 ) of the gas permeable nonporous layer 212 and the substrate after the gas permeable nonporous layer is laminated.

D = F-E (1)

The basis weight of the gas-permeable non-porous layer 212 and the substrate is a value measured as mass per unit area according to JIS1913:2010 General nonwoven fabric test method 6.2.

The thickness of the gas-permeable non-porous layer 212 is preferably 10 um or more and 500 um or less, and more preferably 20 um or more and 200 um or less. The thickness of the gas-permeable non-porous layer 212 is a value measured according to JIS1913:2010 General Nonwoven Fabric Test Method 6.1 Thickness Measurement Method.

(Microbial support layer 213)
The microorganism support layer 213 is a layer that holds microorganisms on its surface or inside, has a space inside where the microorganisms can grow, and allows organic matter in the water to pass through. Examples of materials for the microorganism support layer 213 include Examples of the material for the porous sheet include a porous sheet such as a mesh, a woven fabric, a nonwoven fabric, a foam, or a microporous membrane. The material for the porous sheet is a polyolefin resin, a polystyrene resin, a polyester resin, a polyvinyl chloride resin, an acrylic resin, or a 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, polyimide, polyphenylene sulfide, para- and meta-aramid, polyarylate, carbon fiber, glass Examples of the material include fibers, aluminum fibers, steel fibers, ceramics, etc. In consideration of microbial adhesion and processability, polyolefin resins, polyester resins, polyamide resins, acrylic resins, polyurethane resins, and carbon fibers 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 microbial support layer 213 is preferably 5 um or more and 2000 um or less, and more preferably 20 um or more and 500 um or less. The thickness of the microbial support layer 213 is the value measured according to JIS1913:2010 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 increases the roughness and membrane potential of the substrate 211 surface, improving microbial adhesion. For example, the surface treatment may involve graft polymerization of glycidyl methacrylate and then reacting with diethylamine or sodium sulfite. Alternatively, the surface treatment may involve graft polymerization of glycidyl methacrylate and then reacting with ammonia or ethylamine.

(Method of manufacturing gas supplier 10)
The manufacturing method of the gas supplier 10 of this embodiment is described, for example, in WO2019/189552, so the description will be omitted here.

According to the wastewater treatment device 100 of this embodiment, gas from the gas supply source 53 flows through the gas flow path S and passes through the gas passage hole 13, and the gas passing through the gas passage hole 13 is supplied into the wastewater W via the sheet laminate 21. This supplies oxygen to the microorganisms in the wastewater W, activating the microorganisms, and the organic matter or nitrogen source in the wastewater W can be efficiently decomposed by the activity of the microorganisms to purify the wastewater.

The sheet laminate 21 of this embodiment contains the substrate 211, which is a microporous membrane, and the gas-permeable non-porous layer 212, so that the purification performance of the wastewater treatment device 100 can be maintained.

That is, since the substrate 211 is a highly smooth microporous film, the substrate 211 can be covered with the gas permeable non-porous layer 212 without causing defects in the gas permeable non-porous layer 212. As a result, waterproofness can be obtained even if the gas permeable non-porous layer 212 covering the substrate 211 is thin. Therefore, the waterproofness of the sheet laminate 21 can be improved without impairing the air permeability of the sheet laminate 21. Furthermore, by covering the substrate 211 with the gas permeable non-porous layer 212, the pores of the substrate 211 (microporous film) can be prevented from becoming hydrophilic. Therefore, the sheet laminate 21 can maintain its waterproofness for a long period of time. From the above, if the gas sending layer 12 is covered with the sheet laminate 21 of this embodiment, gas can be supplied by passing through the gas sending layer 12 side into the wastewater W through the sheet laminate 21 without liquid permeating to the gas sending layer 12 side. Therefore, the purification performance of the wastewater treatment device 100 is maintained. Furthermore, according to this embodiment, by inserting the gas-delivery layer 12 into the bag formed from the sheet laminate 21, it is possible to easily achieve a state in which the gas-delivery layer 12 is covered with the sheet laminate 21.

Furthermore, according to the sheet laminate 21 of this embodiment, the inclusion of the microbial support layer 213 can improve the purification performance of the wastewater treatment device 100.

In other words, the sheet laminate 21 contains a microbial support layer 213, which allows the microorganisms to adhere to the microbial support layer 213. This allows a sufficient amount of gas to be continuously supplied to the microorganisms, ensuring that the microorganisms are continuously activated. This improves the purification performance of the wastewater treatment device 100.

Furthermore, according to this embodiment, the sheet laminate 21 is laminated in the order of the microbial support layer 213, the substrate 211, and the gas-permeable non-porous layer 212, so that the outermost layer of the sheet laminate 21 that comes into contact with the wastewater W can be constituted by the microbial support layer 213. Therefore, the microorganisms can be reliably attached to the microbial support layer 213, and the microorganisms can be reliably activated. Therefore, the purification performance of the wastewater treatment device 100 can be reliably improved. In particular, when the microorganisms contained in the wastewater W are aerobic microorganisms, the aerobic microorganisms gather on the sheet laminate 21 by supplying gas into the wastewater W through the sheet laminate 21. Therefore, many microorganisms adhere to the microbial support layer 213, and the purification performance of the wastewater treatment device 100 is significantly improved.

The sheet laminate 21 preferably has an oxygen supply rate Q ( _gO2 / ^m2 /day) of 25 g/m2/day or more, more preferably 26 g/ ^m2 /day or more, and even more preferably 27 g/ ^m2 /day or more, as determined by ^the method described below in (Oxygen Supply Test). The upper limit of the oxygen supply rate Q is preferably 60 g/ ^m2 /day, for example.

(Oxygen supply performance test)
Ion-exchanged water is poured into a sealed tank having a cubic shape with one side length of 7 cm and one vertical side formed of a membrane, and the oxygen concentration in the sealed tank is continuously measured while stirring the ion-exchanged water by rotating a stirrer rotor in an environment of 23 to 27°C. The ion-exchanged water is added with sodium sulfite at a concentration of 100 mg/L and cobalt chloride at a concentration of 1.5 mg/L or more. The stirrer used is "HE-20GB" manufactured by Koike Precision Machinery Manufacturing Co., Ltd., and the rotation speed is set to 7 in the HIGH range. The oxygen supply performance is evaluated in an environment of 23°C to 27°C, and an approximation line is obtained from the correlation with the common logarithm Y=log10(Cs-C) of the oxygen deficiency against time t (h) from the time series data of the measured oxygen concentration, and the slope Z of Y against time t is obtained. Cs is the saturated oxygen concentration in the liquid phase at the measurement temperature T, and C is the measured oxygen concentration in the liquid phase at the measurement time t. From the slope Z, the oxygen supply rate Q (gO ₂ /m ² /day) is calculated according to the following formula (2).

The following is an explanation of a method for aerobic biological treatment of organic water to be treated, and in particular, a biological treatment method using an oxygen-permeable membrane (synonymous with oxygen-dissolving membrane, waterproof air-permeable sheet, waterproof oxygen-permeable film, air-permeable sheet, waterproof air-permeable sheet, etc.) to dissolve oxygen in the water to be treated (also called wastewater or effluent) in a reaction tank, or in microorganisms or biofilms present on the surface of the oxygen-dissolving membrane (hereinafter, a tank containing an oxygen-dissolving membrane will be referred to as an MABR tank. Also, a wastewater treatment method using an MABR tank will be referred to as the MABR method), and the wastewater treatment method, wastewater treatment device, wastewater treatment system, and operation and control methods of the wastewater treatment device are disclosed. The wastewater treatment device system and operation and control methods of the wastewater treatment device disclosed below are not limited to the present invention, but are examples that can be widely applied in wastewater treatment using the MABR method. Therefore, in the examples shown below, unless otherwise specified, the composition and properties of the water to be treated, the treatment method for a specific composition contained in the water to be treated, the amount of water to be treated, the material of the oxygen dissolving membrane, the type of oxygen dissolving membrane (flat plate type, hollow fiber type, spiral type, etc.), the configuration and structure of the oxygen dissolving membrane structure, the method of contacting the wastewater with the oxygen dissolving membrane (whether the water to be treated is held inside the oxygen dissolving membrane structure or is present outside it), the installation method of the oxygen dissolving membrane, the addition of nutrients, the adjustment of water temperature, ORP, pH, etc., the method, procedure and method of supplying oxygen (air) to the oxygen dissolving membrane, the volume and installation method of the tank containing the oxygen dissolving membrane, other wastewater treatment methods, the area load of organic matter on the oxygen permeable membrane, the volume load of organic matter on the tank containing the oxygen permeable membrane, monitoring of the water to be treated, etc. are not particularly limited and can be applied to all of the examples disclosed below unless otherwise specified.

The compositions contained in the treated water include, for example, organic matter (components expressed as BOD, COD, TOC, TOD, etc., lipids, proteins, polysaccharides, amino acids, monosaccharides, higher fatty acids, carbohydrates, organic compounds (hydrocarbons such as linear or cyclic saturated or unsaturated hydrocarbons, aromatic hydrocarbons, aliphatic hydrocarbons, etc.; alcohol compounds; ether compounds; amine compounds; halogen compounds; aldehyde compounds; ketone compounds; carboxylic acid compounds; ester compounds; amide compounds; acid chloride compounds; nitro compounds; sulfo compounds, etc.)), ammonia, ammonium compounds, nitrite compounds, etc. compounds, nitric acid compounds, organic phosphorus compounds, thiram, simazine, thiobencarb, dioxane, chlorinated hydrocarbons, benzene, chlorophyll a, normal hexane extracts, oils, heavy metals (copper, zinc, soluble iron, soluble manganese, chromium, hexavalent chromium, cadmium, lead, arsenic, mercury, alkyl mercury (metal organic compounds), selenium), boron and its compounds, fluorine and its compounds, cyanide compounds, phenols, dioxins, endocrine disruptors, pesticides, polychlorinated biphenyls, low-boiling organic halogen compounds such as trichloroethylene, dioxane, solids (SS, MLSS, VSS, etc.).

Examples of nutrients include nitrogen compounds, phosphorus compounds, etc.

Other wastewater treatment methods include, for example, sedimentation, grit basins, settling tanks, sedimentation methods using inclined plates to promote sedimentation, coagulation separation (using aluminium sulfate, polyaluminium chloride, ferric chloride, ferrous chloride, polyferrous sulfate, etc. as coagulants), flotation, oil-water separators, pressurized flotation separators, clarification filtration, sand filtration, multi-layer filtration, upflow filtration, coagulation filtration, pH adjustment, chemical oxidation/reduction (hyponitrogen oxide, ozone oxidation, Fenton oxidation, chemical reduction), activated carbon adsorption, stirring tank adsorption, Fixed bed adsorption, moving bed adsorption, ion exchange, membrane separation (microfiltration, ultrafiltration, nanofiltration, reverse osmosis, diffusion dialysis membrane), electrodialysis, sludge dewatering (use of filter aids, use of coagulants, water washing, heat treatment, freezing and thawing, vacuum filtration, pressure filtration, pressure roll dewatering, screw press, centrifugal dewatering, multiple disk type dewatering), sludge incineration (fluidized bed incinerator, vertical multi-stage incinerator, horizontal rotary incinerator, stepped stoker incinerator), standard activated sludge process, modified aeration process, extended aeration process, plug flow method, step aeration method, complete mixing method, contact oxidation method, oxidation ditch method, batch activated sludge method, oxygen activated sludge method, deep/ultra-deep aeration method, membrane separation activated sludge method, trickling filter method, contact aeration method, aerobic filter method, carrier addition method (bound immobilization method, entrapped immobilization method), anaerobic filter method, anaerobic fluidized bed method, upflow anaerobic sludge bed, EGSB method, two-phase fermentation system, circulating nitrification/denitrification method, HAP method, MAP method, biostabilization pond method, aerated lagoon, screen, hydroxide method, co-processing method, These include precipitation, substitution, sulfide, ferrite, iron powder, sulfite reduction, iron (II) salt reduction, electrolytic reduction, adsorption, biological reduction, sparingly soluble salt coagulation precipitation (calcium fluoride, hydroxide coprecipitation), alkali chlorine, electrolytic oxidation, sparingly soluble complex compound precipitation, acid decomposition combustion, boiling high-temperature incineration, wet heat decomposition, ammonia stripping, discontinuous point chlorination, volatilization, crystallization, acid precipitation, salting out, stripping, hydrolysis, by-product and valuable material recovery, etc. In addition, in a wastewater treatment device including multiple tanks that performs the wastewater treatment methods exemplified above, the tank contents may be extracted from any tank and added to another tank and returned.

Organisms used in biological treatment include, for example, bacteria (Zoogloea, Beggiatoa, Sphaerotilus, Thiothrix, Nocardia, Alcaligenes, Pseudomonas, Bacillus, Aerobacter, Flavobacterium), cyanobacteria (Microcystis, Phormidium, Coelosphaerium, Oscillatoria, Anabaena), green algae (Chlamydomonas, Dictyosphaerium, Scenedesmus, Closterium), diatoms (Melosira, Cyclotella, Fragilaria, Synedra, Cymbe), and lla), fungi (Fusarium, Zoophagus, Mucor, Saprolegnia, Rhodotorula, Leptomitus, Trichoderma, Geotricum, Sepedomium, Ascoidea, Trichosporon, Phona, Pythium, Arthrobotorys), protozoa such as ciliates (Nectostomata, Trichostomata, Suckerostoma, Hymenostomata, Chlorotricha, Heterotricha, Hypotrichum), flagellates (Promastigera, Euglenida), sarcozoans (Heliozoa, Amoebida, Testate Amoebida), metazoans such as flatworms, saccharomyces, mollusks, annelids, tardigrades, and arthropods.

The area load of organic matter on the oxygen-permeable membrane is preferably, for example, 3 to 2000 g COD _Cr /m ² /day or 2 to 1500 g BOD /m ² /day. The volume load of organic matter on a tank containing the oxygen-permeable membrane is preferably 0.1 to 20 kg COD _Cr /m ³ /day or 0.1 to 15 kg BOD /m ³ /day.

Examples of techniques for monitoring the treated water include water temperature, pH, ORP (oxidation-reduction potential), BOD, COD (COD _Cr , COD _Mn ), TOC, TOD, nitrate nitrogen, nitrite nitrogen, ammonia nitrogen, total nitrogen, phosphorus, chlorophyll a, normal hexane extract, oil, heavy metals (copper, zinc, soluble iron, soluble manganese, chromium, hexavalent chromium, cadmium, lead, arsenic, mercury, alkyl mercury (metal organic compound), cyanide), phenols, dioxins, endocrine disruptors, pesticides, polychlorinated biphenyls, low-boiling organic halogen compounds such as trichloroethylene, electrical conductivity, salt concentration, DO, solids concentration (SS, MLSS, VSS, etc.), turbidity, transparency, transparency, unpleasant odors and tastes, biotoxic substances, coliform bacteria, O157, Cryptosporidium, microbial activity, microbial flora, genetic indicators of microorganisms present inside, and microbial protein concentration. The monitoring location may be within the MABR tank, the inflow path or outflow path of the MABR tank, or any location in a series of wastewater treatment equipment including the MABR tank.

Specific examples of wastewater treatment methods using oxygen-permeable membranes, wastewater treatment devices, wastewater treatment systems, and methods for operating and controlling wastewater treatment devices are described below.

(Method of solid-liquid separation)
The solid-liquid separation combined with the MABR system described below is effective in improving the efficiency of solid-liquid separation. "Improvement of efficiency" means, for example, improvement, maintenance, stabilization, etc. of solid-liquid separation performance.

To efficiently separate solids and liquids, an inclined plate can be placed in the tank in which the MABR is installed, the oxygen-permeable membrane itself can be used as the inclined plate, or the back side of the oxygen-permeable membrane can be made into an inclined plate.

In order to separate the sludge in the biological treatment water into solid and liquid in a biological treatment tank containing an oxygen-permeable membrane, a partition plate may be provided on the wastewater outlet side of the biological treatment tank to divide the biological treatment tank into a biological treatment chamber and an upward flow channel on the wastewater outlet side, and the biological treatment water from the biological treatment chamber may be upwardly circulated in the upward flow channel at an LV of 0.01 to 10 m/h. A biological treatment method may also be used in which the supernatant water is discharged to the outside of the tank from the wastewater outlet at the upper part of the upward flow channel. Furthermore, a partition plate may be provided in the biological treatment chamber along the partition plate. This allows a circulation channel to be formed between the partition plate and the partition plate, both of whose upper and lower parts are connected to the biological treatment chamber. This biological treatment method for organic wastewater is characterized in that a part of the biological treatment water in the biological treatment chamber is upwardly circulated in the circulation channel between the partition plate and the partition plate at an LV greater than the LV in the upward flow channel. The above method is particularly effective for efficient solid-liquid separation, for maintaining sludge and microorganisms in a stable state, and for significantly reducing the amount of sludge generated. It is also effective for improving the treatment efficiency through high-load operation and stabilizing the quality of treated water.

A TOC component removal device for an ultrapure water production system, which is characterized by having a microbial carrier made of a synthetic resin sponge body with an open-cell structure, which is provided with a continuous space through which water can flow from the surface and which holds microorganisms in the continuous space, an aeration means for fluidizing the carrier holding the microorganisms and supplying the necessary oxygen to the microorganisms, a biological treatment tank having an opening smaller than the size of the carrier and provided with a carrier outflow prevention material that prevents the carrier from being discharged by mixing with the treated water, and a microfilter device or ultrafiltration device that separates microorganisms from the treated water discharged from the biological treatment tank and captures fine particles of the carrier generated by fluidization in the biological treatment tank. The above method is particularly effective for reliably assimilating and decomposing the TOC components and producing ultrapure water, even if the TOC components in the water containing trace organic matter from which ultrapure water is to be produced increase.

A wastewater treatment device having a reaction tank for biologically treating organic wastewater containing BOD components by the MABR method, and a separation mechanism for separating the treated water obtained in the reaction tank from sludge using a membrane, wherein the reaction tank includes an anoxic biological treatment tank and a first biological treatment tank and a second biological treatment tank to which oxygen necessary for the biological treatment is supplied, the organic wastewater is continuously flowed into the first biological treatment tank and biologically treated in the first biological treatment tank and the second biological treatment tank, the treated water and sludge are separated in the second biological treatment tank by a membrane installed in the tank, at least a portion of the sludge in the second biological treatment tank is returned to the anoxic biological treatment tank, and at least a portion of the sludge in the anoxic biological treatment tank is supplied to at least the first biological treatment tank, the MLSS load in the first biological treatment tank is higher than the MLSS load in the second biological treatment tank, and the value of the following formula (3) in the first biological treatment tank and the second biological treatment tank is less than 1.
(Sludge retention amount in the first biological treatment tank × retention time) / (Sludge retention amount in the second biological treatment tank × retention time) (3)
The above-mentioned apparatus is particularly effective for improving the filterability of sludge in a continuous membrane separation activated sludge process.

A wastewater treatment method for biologically treating wastewater using a biological treatment tank containing biological sludge and an oxygen-permeable membrane in a tank provided with a wastewater inlet and a treated water outlet, the method comprising: a biological treatment step in which, while the introduction of the wastewater from the wastewater inlet and the discharge of the treated water from the treated water outlet are stopped, the wastewater in the biological treatment tank is stirred and the wastewater is biologically treated by the biological sludge; and a wastewater introduction and treated water discharge step in which, between the stopping of the stirring of the wastewater in the biological treatment tank and the formation of a sludge blanket of the biological sludge in the biological treatment tank, the introduction of the wastewater from the wastewater inlet and the discharge of the treated water from the treated water outlet are started, and the biological treatment step and the wastewater introduction and treated water discharge step are started in sequence and repeated. The method is particularly effective as a wastewater treatment method capable of obtaining biological sludge with high settling properties.

(Method of removing nitrogen components)
The application example of the MABR method shown below is effective in improving the efficiency of wastewater treatment. For example, efficiency means improving, maintaining, and stabilizing wastewater treatment performance. It is particularly effective in improving the efficiency of nitrogen component removal.

A nitrification apparatus comprising: a plug-flow nitrification tank including an oxygen-permeable membrane for receiving a liquid to be treated and biologically nitrifying the liquid; a first liquid supply device for supplying a part of the liquid to be treated from one end of the nitrification tank; a first pH adjusting device for adjusting the pH of the liquid to be treated supplied from the first liquid supply device to 5 to 9.7; a second liquid supply device for supplying another part of the liquid to be treated from an intermediate part of the plug-flow nitrification tank; and a second pH adjusting device for adjusting the pH of the liquid to be treated supplied from the second liquid supply device to 6.5 to 11.5. The above apparatus is particularly effective for maintaining the pH in the nitrification tank in a range where the activity of nitrifying bacteria is high, even when the pH, NH ₄ ⁺ concentration, or alkalinity of the liquid to be treated fluctuates, when biological nitrification is performed using a plug-flow nitrification tank. It is even more effective to hold a microbial carrier such as a sponge on the surface of the oxygen-permeable membrane.

A method for treating nitrogen-containing liquid in which oxygen supplied from an oxygen-permeable membrane is used to react ammonia nitrogen and nitrite nitrogen with anammox bacteria to denitrify the liquid. The method is particularly effective for retaining a large amount of anammox bacteria, efficiently reacting ammonia nitrogen and nitrite nitrogen to denitrify the liquid, and efficiently separating the generated nitrogen gas to continue the denitrification. It is even more effective to place a carrier such as a sponge on the surface of the oxygen-permeable membrane.

A method for treating organic wastewater in which an anoxic zone consisting of floating carriers and an aerobic zone are provided in a reaction tank containing an oxygen-permeable membrane, with an aeration pipe as the boundary, raw wastewater and circulating treated water are mixed and flowed into the anoxic zone, a denitrification reaction occurs in the anoxic zone using organisms in the raw water, and a nitrification reaction occurs in the aerobic zone using oxygen from the aeration pipe, thereby denitrifying the wastewater. The method is characterized in that the amount of air injected from the aeration pipe or the amount of air supplied to the oxygen-permeable membrane is controlled according to the amount of raw water flowing in. The above method is particularly effective in solving the problem that, in an organic wastewater treatment method in which an anoxic zone and an aerobic zone made of floating carriers are set up vertically in a reaction tank with an aeration pipe as a boundary, raw wastewater and circulating treated water are mixed and flown into the anoxic zone, a denitrification reaction occurs in the anoxic zone using organisms in the raw water, and a nitrification reaction occurs in the aerobic zone using oxygen from the aeration pipe, thereby performing denitrification treatment in the wastewater. When the amount of sewage inflow fluctuates, the denitrification reaction does not occur sufficiently, and as a result, nitrogen is not sufficiently removed.

In a wastewater treatment method including an anaerobic treatment step in which organic wastewater and microbial sludge are mixed in an anaerobic state to promote granulation of the microbial sludge, an oxygen supply step in which oxygen is supplied to the mixed liquid of the organic wastewater and microbial sludge obtained in the anaerobic treatment step, and a precipitation treatment step in which sludge in the mixed liquid that has been through the oxygen supply step is precipitated, the ORP of the mixed liquid of the organic wastewater and microbial sludge in the anaerobic treatment step is kept at -100 mV or less, and oxygen may be supplied in the oxygen supply step using a gas supplier.

A water treatment facility that includes a filter layer that filters raw water in an upward flow, and an aeration device that supplies gas to generate air bubbles below the filter layer and purifies the filter layer by causing the air bubbles to rise through the filter layer, the aeration device having a main air supply pipe arranged below the filter layer and a plurality of branch pipes branching off from the main air supply pipe, the branch pipes having a connection portion connected to the main air supply pipe and an opening portion for releasing gas introduced from the main air supply pipe through the connection portion to generate air bubbles below the filter layer, and the branch pipes having a turn portion between the connection portion and the opening portion where the flow direction of the gas turns from downward to upward, and at least the turn portion can be divided into one and the other portions that can be attached and detached from each other, and may have a gas supply body in at least a part of the water treatment facility. The lower part of the gas supply body may have a main gas supply pipe and a plurality of branch pipes branched off from the main gas supply pipe. Specifically, the branch pipe has a connection part connected to the main gas supply pipe and an opening part that releases gas introduced from the main gas supply pipe through the connection part to generate air bubbles below the filter layer. The branch pipe may have a turn part between the connection part and the opening part where the flow direction of the gas turns from downward to upward, and may be detachable at least at the turn part.

A wastewater treatment device including a biological reactor having an oxygen-permeable membrane, with a flow path through which raw water flows in from the bottom and is returned from the top to the bottom of the biological reactor. The device is particularly effective in maintaining the microbial flora involved in nitrogen treatment and in improving, maintaining, and stabilizing treatment performance.

Wastewater treatment equipment that uses the MABR method in the aerobic tank in the A2O process. The above equipment is particularly effective in improving, maintaining, and stabilizing the microbial flora and treatment performance involved in nitrogen treatment. It is also effective to extract a portion of the sludge generated in any tank in the A2O process and feed it into any tank in the A2O process.

A biological treatment device for organic waste, comprising a biological treatment tank containing an oxygen-permeable membrane in which a fluidized bed of biological carrier particles is formed, a circulation system for circulating liquid so as to give an upward flow rate to the biological treatment tank, a circulation pump provided in the circulation system, and a means for intermittently changing the amount of circulating water in the circulation system, characterized in that the fluidized bed is normally operated at a low expansion rate and intermittently operated at a high expansion rate. The device is particularly effective in maintaining the microbial flora involved in nitrogen treatment and in improving, maintaining, and stabilizing treatment performance.

A treatment device for wastewater containing nitrate and nitrite, comprising: a hydrogen donor adding means for adding a hydrogen donor to wastewater containing nitrate and nitrite after nitrifying nitrogen components in the water to be treated into nitrate or nitrite using the MABR method; a denitrification tank for anaerobically biologically treating the wastewater to which the hydrogen donor has been added; an ultraviolet absorbance sensor for measuring the nitrate and nitrite concentrations in the wastewater; an ion electrode sensor for measuring the nitrate concentration in the wastewater; and a control unit for controlling the amount of the hydrogen donor added to the wastewater by the hydrogen donor adding means based on the nitrate and nitrite concentrations in the wastewater determined from the nitrate and nitrite concentrations measured by the ultraviolet absorbance sensor and the nitrate concentration measured by the ion electrode sensor. The device is particularly capable of quickly measuring the nitrate and nitrite concentrations in the water to be treated, and is effective in maintaining the microbial flora involved in nitrogen treatment and improving, maintaining, and stabilizing treatment performance.

After the nitritation of ammonia nitrogen using the MABR method, an autotrophic denitrifying microbial sludge that generates nitrogen gas by reacting ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor is treated in a liquid containing ammonia nitrogen and nitrite nitrogen with a specific gravity of 0.8 to 1.5, a pore size of 5 to 5,000 μm, a porosity of 10 to 90%, and a specific surface area of 500 to 10,000 m ² /m ³ . ammonia nitrogen and nitrite nitrogen in the liquid to be treated, the molar ratio of ammonia nitrogen to nitrite nitrogen being 0.5 to 2, the concentrations of ammonia nitrogen and nitrite nitrogen in the liquid to be treated being 5 to 1000 mg/L and 5 to 200 mg/L, respectively; and the amount of carriers held in the denitrification tank being 10 to 75% by volume of the amount of carriers put into the liquid in the tank. The above-mentioned method is particularly effective for obtaining a denitrification method and apparatus which can retain a large amount of autotrophic microorganisms, increase the denitrification activity per sludge amount, and increase the resistance to inhibitors such as dissolved oxygen, thereby enabling efficient denitrification in a small device, facilitating the start-up of a new device, and eliminating the need for strict oxygen removal. A carrier having the same properties as the above-mentioned granular carrier may be supported or laminated on the surface of the oxygen-permeable membrane.

A method for denitrification in the presence of nitrite nitrogen by the action of denitrifying microorganisms in the denitrification tank that use ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor, in which raw water containing ammonia nitrogen is introduced into a denitrification tank, and denitrification is performed in the presence of nitrite nitrogen by controlling the pH in the denitrification tank by supplying carbon dioxide gas to the denitrification tank, and the nitrite nitrogen is obtained by treating ammonia nitrogen using the MABR method. The above method is particularly effective in denitrifying raw water containing ammonia nitrogen in the presence of nitrite nitrogen by the action of denitrifying microorganisms that use ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor, because it is easy to adjust the pH to a suitable range without using an acid for pH adjustment or strict addition control.

In a method for treating wastewater containing ammonia nitrogen by introducing the wastewater into an aeration tank/MABR tank that holds ammonia oxidizing bacteria and aerating the wastewater, a first gas containing oxygen is supplied using an oxygen-permeable membrane, and a second gas that is substantially oxygen-free or has a lower oxygen partial pressure than the first gas is supplied. The first gas is supplied to an extent that a required DO concentration is obtained in the aeration tank, and the insufficient stirring force is compensated for by the aeration air volume of the second gas, thereby controlling the dissolved oxygen concentration in the aeration tank to 0.5 mg/L or less. The above method is particularly effective in a method for treating wastewater by introducing the wastewater into an aeration tank that holds aerobic bacteria and aerating the wastewater, because it allows the DO concentration in the aeration tank to be controlled as desired, even if the set DO concentration in the aeration tank is low, by obtaining sufficient stirring action in the tank through aeration.

The denitrifying microbial sludge, which generates nitrogen gas by reacting ammonia nitrogen as an electron donor with nitrite nitrogen as an electron acceptor, is treated in a liquid containing ammonia nitrogen and nitrite nitrogen with a specific gravity of 0.8 to 1.5, a pore size of the open cells of 5 to 5,000 μm, a porosity of 10 to 90%, and a specific surface area of 500 to 10,000 m ² /m ^{3 .} a method for treating ammoniacal nitrogen and nitrite nitrogen by adding granular carriers having a particle size of 0.1 to 2 cm, causing the denitrifying microbial sludge to penetrate and adhere to the inside of the granular carriers, and then holding the three-dimensionally supported sludge in a denitrification tank and contacting and reacting with a liquid to be treated containing ammoniacal nitrogen and nitrite nitrogen under anaerobic conditions, wherein the ratio of ammoniacal nitrogen to nitrite nitrogen in the liquid to be treated is 1:0.5 to 2:0 nitrite nitrogen in molar ratio, and the concentrations of ammoniacal nitrogen and nitrite nitrogen in the liquid to be treated are 5 to 1000 mg/L and 5 to 200 mg/L, respectively, the amount of carriers held in the denitrification tank is 10 to 75 volume % of the amount of carriers added to the liquid in the tank, and the nitrite nitrogen is obtained by treating ammoniacal nitrogen using a MABR method. The above-mentioned method is particularly effective as a denitrification method that can retain a large amount of autotrophic microorganisms, increase the denitrification activity per sludge amount, and increase the resistance to inhibitors such as dissolved oxygen, thereby enabling efficient denitrification in a small device, facilitating the start-up of a new device, and eliminating the need for strict oxygen removal. A carrier having the same properties as the above-mentioned granular carrier may be supported or laminated on the surface of the oxygen-permeable membrane.

A method for treating nitrogen-containing wastewater, comprising an ammonia oxidation step in which wastewater containing nitrogen and calcium is contacted with autotrophic bacteria after reducing the calcium concentration in the wastewater to 100 mg/L or less, and then oxidizing at least a portion of the ammonium ions in the wastewater to nitrite ions, and a denitrification step in which the wastewater containing ammonium ions and nitrite ions is contacted with autotrophic ANAMMOX bacteria while inorganic carbon is being supplied, and denitrification is carried out, characterized in that the ammonia oxidation step is carried out under aerobic conditions using oxygen supplied from an oxygen-permeable membrane, the denitrification step is carried out under anaerobic conditions, and carbonate ions or bicarbonate ions are supplied in the ammonia oxidation step to adjust pH. The method is particularly effective for obtaining a method for treating nitrogen-containing wastewater that can remove problems caused by calcium components remaining in the wastewater and perform stable nitrogen treatment when treating wastewater containing calcium and nitrogen.

A wastewater treatment system that performs nitrification and denitrification by intermittently stopping the supply of oxygen-containing gas to the oxygen-permeable membrane in the treatment of organic nitrogen and ammonia nitrogen using the MABR method. The above-mentioned system is effective for performing nitrification and denitrification with a small installation area and tank volume.

In the treatment of organic nitrogen and ammonia nitrogen using the MABR method, this wastewater treatment device performs nitrification and denitrification by measuring the nitrate or nitrite concentration in the water being treated in the MABR tank and feedback-controlling the amount of oxygen-containing gas supplied to the oxygen-permeable membrane based on the measured value. The device is particularly effective in maintaining the microbial flora associated with nitrification and denitrification, and in improving, maintaining, and stabilizing nitrification and denitrification performance.

A method for biologically treating nitrogen-containing water, in which a hydrogen donor is intermittently added to a denitrification reaction tank into which water to be treated containing nitric acid or nitrite flows, to reduce the nitric acid or nitrite to nitrogen gas, the method being characterized in that the hydrogen donor addition rate (v), the amount of hydrogen donor added per unit time (X), the hydraulic residence time (T) calculated by dividing the total volume of the reaction tank by the flow rate of water flowing into the reaction tank, the number of intermittent addition cycles of the hydrogen donor (N) obtained by dividing the hydraulic residence time (T) by the time per one cycle of intermittent addition consisting of addition and stoppage of the hydrogen donor, the concentration (M) of the hydrogen donor to be added, the ratio (D) of the hydrogen donor addition time to the time per one cycle of the intermittent addition, and the hydrogen donor supply stop time (ST) per one cycle of the intermittent addition are set so as to satisfy the following formula (B ₎ in response to an increase or decrease in the amount of nitric acid or nitrite calculated from the product of the concentration of nitric acid or nitrite in the water to be treated flowing into the reaction tank and the amount of water to be treated flowing into the reaction tank. The nitric acid or nitrous acid may be discharged water from a MABR tank installed separately from the denitrification reaction tank, or may be return water from a MABR tank installed downstream of the denitrification reaction tank, or may be discharged water from a MABR tank installed upstream of the denitrification reaction tank. Nitric acid or nitrous acid may be obtained by oxidation of organic nitrogen or ammonia nitrogen by installing an oxygen-permeable membrane in the denitrification reaction tank. The above method is particularly effective for providing a method and treatment device for treating nitrogen-containing water that can ensure stable treated water quality even if the nitrogen concentration or flow rate in the water to be treated fluctuates.
v=X・T・(100−D)/(N・S _T・D・M) (4)

A nitrification treatment method in which ammoniacal nitrogen in raw water is biologically nitrified into nitrite nitrogen or nitrate nitrogen by nitrifying bacteria in a nitrification tank by a granular method, the method being characterized in that oxygen is supplied using an oxygen permeable membrane, carbon dioxide gas is supplied in a gaseous state as inorganic carbon to the nitrification tank, and the conversion load of the ammoniacal nitrogen flowing into the nitrification tank per unit tank volume per day to the nitrite nitrogen or nitrate nitrogen is 0.5 kg-N/ ^m3 /day or more. The method is particularly effective for obtaining a nitrification treatment method that can inexpensively and easily supply inorganic carbon required for the nitrification treatment of ammoniacal nitrogen in raw water.

(Method of homogenizing wastewater composition and additives in MABR tank)
The application example of the MABR method shown below is effective in improving the efficiency of wastewater treatment by homogenizing the inside of the MABR tank. Efficiency means, for example, improving, maintaining, and stabilizing the wastewater treatment performance.

It is possible to equalize the inside of the tank by moving the oxygen-permeable membrane structure using power. For example, an air cylinder or a vibration motor can be used as the power source, and these power sources can be converted into reciprocating motion using an eccentric cam or the like and transmitted to the oxygen-permeable membrane structure.

The inside of the tank can be stirred by devising an inflow path for the water to be treated. For example, the flow rate of the water to be treated can be increased by using the principle of a siphon, and this flow can be used to stir the inside of the tank. In addition, the flow can be controlled so that the inside of the tank is stirred evenly by using a water guide plate, or the flow of the water to be treated can be made to come into contact with an oxygen permeable membrane. In addition, by connecting a manifold or header to the outlet of the water to be treated, the flow can be controlled so that the inside of the tank is stirred evenly, or the flow of the water to be treated can be made to come into contact with an oxygen permeable membrane.

By using step inflow, the concentration of organic matter being treated in the tank can also be made uniform.

A MABR type biological treatment device in which a baffle is provided only on an upper portion of the inner circumferential surface of the tank, the baffle extends in the vertical direction and also in the centripetal direction from the inner circumferential surface of the tank, the width t of the baffle in the centripetal direction is 5-20% of the diameter _D1 of the tank body, the vertical length _H2 of the baffle below the water level is 5-20% of the water depth _H1 of the tank body, the height _H3 of the upper edge of the rotor from the bottom surface of the tank body is 50-70% of the water depth _H1 of the tank body, and the height _H5 of the lower edge of the rotor from the bottom surface of the tank body is 30-50% of the water depth _H1 of the tank body. By using the above device, a MABR type biological treatment device in which the fluidity of the water to be treated is particularly good and biological treatment efficiency is high can be effectively obtained.

For powered mixing, the following devices can be used to mix the wastewater: an air lift using an upward air flow, a mixer with blades, a submersible pump, or a pump installed outside the tank with piping installed in the MABR tank.

A biological treatment device that combines a MABR tank with an aeration tank used in the activated sludge method or the fluidized carrier method, in which the water to be treated in the MABR tank and the aeration tank is circulated and stirred by the upward flow obtained in the aeration tank. Or, a device that biologically treats organic wastewater in multiple biological treatment tanks, in which the first biological treatment tank generates a first biological treatment water with an increased number of dispersed bacteria by decomposing organic matter with dispersed bacteria, and the second biological treatment water is generated in the second biological treatment tank, which is the MABR tank in the latter stage. In this biological treatment device for organic wastewater, the first biological treatment tank and the second biological treatment tank have tower bodies of the same shape and size, the tower bodies are 1 to 11 m high, and a membrane separation tank into which the biological treatment liquid is circulated from the final stage biological treatment tank can be constructed. The first biological treatment tank and the second biological treatment tank may be installed in the reverse order. By using the above device, it is possible to effectively obtain a biological treatment device for organic wastewater that is particularly easy to install, reduces work at height, and saves space.

In a method for treating wastewater by storing wastewater in a biological treatment tank and installing a gas supplier in the biological treatment tank, the viscosity of the wastewater in the biological treatment tank may be set to 10 mPa·s or less. In addition, aeration may be performed in the biological treatment tank to promote mixing and biological treatment.

A gas supply may be used in a water treatment facility that includes a membrane separation section that separates organic matter-containing water to be treated using a membrane, and a pretreatment section that is arranged upstream of the membrane separation section and adjusts the biopolymer concentration in the water to be treated to be equal to or lower than a predetermined threshold value, the pretreatment section including a biopolymer concentration measurement section that measures the biopolymer concentration in the water to be treated before membrane separation, a fouling-inhibiting substance addition section that adds a fouling-inhibiting substance to the water to be treated before membrane separation to suppress fouling when the biopolymer concentration measured by the biopolymer concentration measurement section becomes equal to or higher than a predetermined threshold value, and a biological contact filtration section that has a filter medium on which microorganisms having a water purification effect are grown, upstream of the biopolymer concentration measurement section and the fouling-inhibiting substance addition section, and uses the filter medium to filter the water to be treated before membrane separation, and the predetermined threshold value is set to any value in the range of 9 μg/L to 100 μg/L. In addition, a gas supply may be used in the water treatment method, which includes a membrane separation process for membrane-separating water containing organic matter, and a pretreatment process for adjusting the biopolymer concentration in the water to be treated to a predetermined threshold or less before the membrane separation process, in which the pretreatment process filters the water to be treated using a filter medium on which microorganisms having a water purification effect are grown, measures the biopolymer concentration in the filtered water to be treated, and if the measured biopolymer concentration is equal to or greater than the predetermined threshold, adds a fouling inhibitor to the water to be treated to be subjected to membrane separation in the membrane separation process, and if the measured biopolymer concentration is less than the predetermined threshold, does not add a fouling inhibitor to the water to be treated to be subjected to membrane separation in the membrane separation process, and the predetermined threshold is set to any value in the range of 9 μg/L to 100 μg/L.

A water treatment device in which a biological treatment tank and a membrane separation tank equipped with a submerged membrane separation device that performs membrane separation of treated water from the biological treatment tank are integrated, the reaction tank and the membrane separation tank are separated by a first partition with an open lower end, the reaction tank is divided by a second partition with an open upper and lower ends into an upstream region with a first air diffuser installed at the bottom and a downstream region adjacent to the membrane separation tank via the first partition, and the bottom surface is inclined so that the height increases from the upstream region toward the membrane separation tank. A gas supplier may be used for at least a part of the biological treatment tank.

To equalize the inside of the tank, raw water can be passed through a tank holding an oxygen-permeable membrane by alternately switching between upward and downward flow every hour to 30 days.

The wastewater treatment device can be operated so that the circulation pump is operated only when too much biofilm has built up on the surface of the oxygen-permeable membrane to remove the biofilm, or the wastewater treatment device can be operated so that the circulation pump is operated for 1 minute to 1 day every 1 hour to 30 days to prevent too much biofilm from building up.
A method for operating a biological treatment tank, the biological treatment tank being cylindrical or polygonal with a horizontal bottom surface or a bottom surface that is convex upward or downward, and an angle between a line connecting an end portion and a center portion and a horizontal line is 0.3 degrees or more and 60 degrees or less, a screw-type or impeller-type agitator for agitating the liquid to be treated is provided in the center portion, and a sediment removal pipe is disposed in the center portion of the bottom surface, the operating method comprising alternating between normal operation and sediment removal operation, and rotating the screw-type or impeller-type agitator during normal operation. In this operating method, a downward flow toward the bottom is generated in the center of the biological treatment tank, and an upward flow toward the water surface is generated on the sides of the biological treatment tank, and during sediment extraction operation, the screw-type or impeller-type agitator is rotated in the opposite direction to that during normal operation, thereby generating an upward flow toward the water surface in the center of the biological treatment tank, and a downward flow toward the bottom is generated on the sides of the biological treatment tank, and the sediments collected in the center of the bottom are discharged from the sediment extraction pipe to the outside of the biological treatment tank. Biological treatment may be performed using a gas supplier.

(Method of combining MABR tank with other wastewater treatment equipment)
The application example of the MABR system shown below is effective in improving the efficiency of wastewater treatment by combining the MABR system with other wastewater treatment methods. Efficiency means, for example, improving, maintaining, and stabilizing wastewater treatment performance.

By connecting MABR tanks in series, the organic matter concentration in the treated water can be efficiently reduced.

A biological treatment method for organic wastewater, in which organic wastewater is passed through an aerobic first biological treatment tank, and the first biologically treated water from the first biological treatment tank is introduced into an aerobic second biological treatment tank. Specifically, it is preferable that the total BOD volume load is 0.5 to 5 kg/m ³ /day, the BOD volume load of the first biological treatment tank is 1 kg/m ³ /day or more, 10 to 90% of the organic components in the organic wastewater are removed in the first biological treatment tank, and the load of SS derived from dispersed bacteria in the first biologically treated water on the carrier in the second biological treatment tank (hereinafter referred to as dispersed bacteria carrier load) is 8 kg-SS/m ³ -carrier/day or less. In addition, it is preferable that at least one of the first biological treatment tank and the second biological treatment tank is an MABR tank, and that the second biological treatment tank contains microorganisms that prey on sludge. By using the above method, it is possible to effectively obtain a biological treatment method for organic wastewater in which bacteria flowing out from the first biological treatment tank are appropriately preyed on and stable biological treatment can be performed.

A biological treatment method for organic wastewater in which biological treatment is carried out under aerobic conditions with a COD _Cr volume load of 1.0 kg/ ^m3 /day or more or a BOD volume load of 0.5 kg/ ^m3 /day or more, the aerobic biological treatment tanks being provided in two or more stages, organic wastewater being introduced into a first biological treatment tank for biological treatment with bacteria, the first biologically treated water containing dispersed bacteria from the first biological treatment tank being passed through a second or subsequent biological treatment tank for biological treatment, the treated water from the second or subsequent biological treatment tanks is subjected to solid-liquid separation in a settling tank, and a portion of the separated sludge is returned to the second or subsequent biological treatment tanks. A biological treatment method for organic wastewater, comprising providing a carrier or an oxygen-permeable membrane for holding micro-animals in a wastewater treatment tank, and the carrier provided in the biological treatment tanks after the second biological treatment tank is a sheet-like carrier made of a synthetic resin foam, with one side having a length of 100 to 400 cm, a side perpendicular thereto having a length of 5 to 200 cm, and a thickness of 0.5 to 5 cm, at least a part of the carrier being fixed vertically to the biological treatment tank directly or via a fixing device, and at least one of the first biological treatment tank and the second biological treatment tank includes an oxygen-permeable membrane. By using the method, particularly in a multi-stage activated sludge process utilizing the predatory action of micro-animals, in high-load treatment with a COD _Cr volume load of 1.0 kg/m ³ /day or more or a BOD volume load of 0.5 kg/m ³ /day or more, filter-feeding micro-animals are actively given priority and the proliferation of aggregate-feeding micro-animals that cause deterioration of treated water quality is suppressed, thereby improving treatment efficiency and treated water quality and reducing the volume of sludge.

By using a screen to remove impurities and solids at any position before the MABR tank, it is possible to improve the quality of the treated water and prevent damage to the oxygen permeable membrane caused by impurities and solids.

By using a coagulation sedimentation device and a coagulation sedimentation tank at any position downstream of the MABR tank, it is possible to obtain good treated water quality.

In addition, good treated water quality can also be obtained by placing a tank filled with activated carbon at any position downstream of the MABR tank and passing the water to be treated through it.

A biological treatment method in which two or more biological treatment tanks are connected in series, organic wastewater is passed through the first biological treatment tank and biologically treated with bacteria, and the first treated water from the first biological treatment tank containing dispersed bacteria is introduced into the second biological treatment tank and biologically treated while allowing microscopic animals to be present in the second biological treatment tank, in which the dissolved oxygen concentration in the first biological treatment tank is controlled to 0.5 mg/L or less, and carriers are present in each of the first and second biological treatment tanks, the first biological treatment tank being an MABR tank or a fluidized bed with a carrier filling rate of 40% or less or a tank containing an oxygen permeable membrane and a carrier filling rate of 40% or less, the second biological treatment tank being an MABR tank or a fluidized bed with a carrier filling rate of 10% or more or a tank containing an oxygen permeable membrane and a carrier filling rate of 10% or less, and the treated water from the second biological treatment tank is subjected to solid-liquid separation, characterized in that 30% or more of the wastewater BOD is decomposed in the first biological treatment tank. By using the above method, it is possible to effectively stabilize the sludge reduction effect in the multi-stage activated sludge process, which utilizes the feeding action of microscopic animals.

A biological treatment method for organic wastewater comprising a first biological treatment step in which the BOD in the organic wastewater is converted into bacterial cells through high-load treatment, and a second biological treatment step in which the converted bacterial cells coexist with microscopic animals that prey on the bacterial cells, the hydraulic retention time (HRT) required in the first biological treatment step for 70% or more but less than 100% of the BOD in the organic wastewater to be converted into bacterial cells as a reference is calculated, and this value is taken as the reference HRT. A liquid is added to the organic wastewater introduced into the first biological treatment step so that the HRT in the first biological treatment step is in the range of 0.75 to 1.5 times the reference HRT, and at least one of the first and second biological treatment steps is an MABR method. By using the above method, it is possible to effectively achieve further improvement in treatment efficiency and reduction in the amount of excess sludge generated while maintaining stable treated water quality, particularly in a multi-stage method that utilizes the predatory action of microscopic animals.

A method for treating organic wastewater containing poorly biodegradable organic matter and readily biodegradable organic matter, comprising two or more steps, the steps being any one of biological treatment, ozone treatment, reverse osmosis membrane treatment, and biological activated carbon treatment, and at least one step being a MABR treatment. Specifically, the method includes a first treatment step of biologically treating the organic wastewater by the MABR treatment, a second treatment step of decomposing at least a part of the poorly biodegradable organic matter by ozone treatment to obtain a decomposition product, a third treatment step of performing reverse osmosis membrane treatment on the decomposition product, and a fourth treatment step of performing biological treatment, in which the biological treatment in the fourth treatment step is preferably performed by MABR treatment or using biological activated carbon, and the poorly biodegradable organic matter is a surfactant. By using the method, it is possible to effectively treat organic wastewater containing poorly biodegradable organic matter and effectively obtain an organic wastewater treatment device capable of sufficiently reducing the TOC concentration in the resulting treated water.
The present invention includes an estimation step of calculating a ratio between the concentration of the reagent and the concentration of the detection substance in the concentrated water after membrane separation while separating water containing a reagent that reacts with microorganisms to generate a detection substance by a reverse osmosis membrane, and estimating the activity level of the microorganisms attached to the reverse osmosis membrane from the calculated ratio, the estimation step including a calculation step of calculating each calculated value which is the ratio between the concentration of the reagent and the concentration of the detection substance measured at time intervals, and a determination step of determining a representative value representing the calculated values from the calculated values within a range of a preset fluctuation range when a plurality of calculated values calculated in succession at each time interval in the calculation step fall within a range of a preset fluctuation range, and the estimation step estimates the activity level of the microorganisms attached to the reverse osmosis membrane based on the representative value, and a gas supply may be used for at least a part of the estimation method of microbial activity. Also, a gas supply may be used for at least a part of the water treatment method and water treatment facility using the estimation method.

A seawater desalination apparatus configured to desalinize seawater by a filtration process using a reverse osmosis membrane device, characterized in that the apparatus includes a mixed water processing section that mixes biologically treated water obtained by biologically treating organic wastewater with a gas supplier as dilution water with seawater, and supplies the mixed water obtained by the mixing to the reverse osmosis membrane device for filtration. A gas supplier may be used in at least a part of the seawater desalination apparatus.

In a wastewater treatment method in which wastewater such as leachate is treated by reverse osmosis membrane treatment after biological treatment, the biological treatment includes a denitrification treatment step, and nitric acid is used as a cleaning liquid for the reverse osmosis membrane used in the reverse osmosis treatment, and the nitric acid-containing cleaning wastewater after cleaning the reverse osmosis membrane is returned to the denitrification treatment step or returned to the previous stage of the denitrification treatment step, at least a part of which may be a gas supplier.

It is effective to prevent condensation water on the lid of the MABR tank from falling into the water being treated in the MABR tank. For example, it is effective to tilt the lid or make the lid double-layered to prevent condensation water from falling, or to use a ventilation device to prevent condensation. A suitable ventilation device for preventing condensation is to install a hygrometer in the gas space of the device, and operate the ventilation device or control the ventilation volume according to the humidity.

A method for operating a biological treatment tank, characterized by controlling the flow rate of oxygen-containing gas supplied to the oxygen-permeable membrane in the MABR tank according to the amount of water flowing in and the organic matter concentration. By using the above method, it is possible to operate the tank with a minimum gas flow rate, resulting in significant energy savings.

(Methods for dealing with fluctuations in organic load)
The application example of the MABR method shown below is effective in streamlining wastewater treatment even when the organic matter concentration and water volume of the treated water fluctuate. Efficiency means, for example, improving, maintaining, and stabilizing wastewater treatment performance.

A method for operating a wastewater treatment system in which biological treatment devices are installed in parallel, the amount of water distributed to each device is controlled according to load fluctuations, and at least one of the biological treatment devices is of the MABR type.

A wastewater treatment device that includes at least a flow rate adjustment tank and a biological reaction tank, the flow rate adjustment tank being installed upstream of the biological reaction tank, organic matter removal by biological treatment being possible, and at least one of the biological reaction tank and the flow rate adjustment tank being an MABR tank. In the wastewater treatment device, it is preferable to control the amount of water to be treated flowing into the biological reaction tank according to the amount of water to be treated and the organic matter concentration of the water to be treated.

In a biological treatment apparatus for organic wastewater, which performs aerobic biological treatment by the MABR method by adding nutrients to organic wastewater so that the amount of nutrients containing nitrogen or phosphorus is appropriate, the biological treatment apparatus for organic wastewater is characterized by having an organic matter concentration measuring means for measuring the organic matter concentration of the wastewater to be treated, and a nutrient addition control means for adding nutrients so that the amount of nutrients relative to the organic matter is approximately the theoretically appropriate amount when the measured organic matter concentration is less than a predetermined value, and adding nutrients so that the amount of nutrients relative to the organic matter concentration is less than the theoretically appropriate amount when the measured organic matter concentration is a high concentration equal to or greater than the predetermined value. In the apparatus, the predetermined value of the organic matter concentration is 2000 mg/L as BOD, and the amount less than the theoretically appropriate amount is preferably 3 or less for nitrogen and 0.7 or less for phosphorus, assuming a BOD of 100. By using the apparatus, particularly high-concentration organic wastewater can be efficiently treated.

A wastewater treatment method for treating organic wastewater, characterized in that the liquid to be treated containing organic matter is supplied to multiple biological treatment tanks arranged in parallel, the organic matter load of one of the multiple biological treatment tanks is set to be 20% to 50% higher than the organic matter load of the other tanks, when the treated water quality of one tank deteriorates and does not meet the operational management standard value of the biological treatment tank, the liquid to be treated of at least some of the other tanks is supplied to the one tank, and when the wastewater treatment state of the one tank meets the operational management standard value of the biological treatment tank, the supply of the liquid to be treated from at least some of the other tanks to the one tank is stopped, at least a part of which may be a gas supply body.

A method for treating organic matter-containing water, characterized in that the organic matter-containing water is biologically treated by oligotrophic bacteria that accumulate by phosphorus deficiency in a biological treatment device that treats organic matter-containing water using the MABR method. It is preferable to combine membrane filtration in the treatment device. It is also preferable that the device has a means for measuring the organic matter concentration and the flow rate of the water to be treated flowing into the device, has a means for adding nutrients containing at least phosphorus to the biological treatment device, and controls the amount of nutrients added according to the organic matter concentration and the flow rate of the water to be treated. By using the above method, it is possible to effectively prevent slime on the membrane surface and biofouling caused by it, particularly in the biological treatment or membrane treatment of organic matter concentration and organic matter-containing water, without using a bactericide, and to perform stable and efficient treatment for a long period of time.

(Method for treating water containing high concentrations of organic matter)
The application example of the MABR method shown below is effective for improving the efficiency of wastewater treatment when treating water containing high concentrations of organic matter. Efficiency means, for example, improving, maintaining, and stabilizing wastewater treatment performance.

A wastewater treatment device characterized by having a fermentation tank at an arbitrary position before the MABR system, which mixes concentrated organic wastewater with a high organic matter concentration and performs high-temperature aerobic fermentation or anaerobic digestion of the mixed liquid. Specifically, the concentrated organic wastewater is preferably sewage wastewater, excess sludge generated from the activated sludge process, industrial wastewater (food factories, chemical factories, electronics processing factories, etc.), and more preferably beet sugar peak cut wastewater, shochu mash wastewater, yeast production wastewater, waste sugar molasses wastewater, or soybean processing wastewater. In addition, it is preferable that the mixed liquid has a CODcr of 10,000 or more. By using the above device, it is possible to efficiently treat concentrated organic wastewater in particular.
This is a treatment method for treating organic waste liquid such as livestock manure and sewage, in which the organic waste liquid is subjected to solid-liquid separation, and then the separated liquid is subjected to denitrification and nitrification treatment, and nitrification/denitrification may be performed using a gas supplier.

A biological treatment method for organic wastewater, comprising: an anaerobic biological treatment step in which organic wastewater is anaerobic biologically treated in an anaerobic tank; and aerobic biological treatment step in which organic wastewater is subsequently aerobic biologically treated in at least one aerobic tank, wherein in the aerobic biological treatment step, biological treatment is performed in a first aerobic tank using aerobic bacteria to produce dispersible bacteria, and in the anaerobic biological treatment step, anaerobically treatment is performed so that the CODcr volume load of the entire aerobic biological treatment step is 10 kg/ ^m3 /day or less and the soluble CODcr volume load is 5 kg/ ^m3 /day or less, and aerobic treatment is performed in the first aerobic tank so that the load of the first aerobically treated water SS on the carrier in the second aerobic tank is 15 kg-SS/ ^m3 -carrier/day or less, and at least one of the biological treatment steps includes an oxygen-permeable membrane. In the above method, it is preferable to introduce the first aerobically treated water containing dispersible bacteria from the first aerobic tank into a second aerobic tank having a carrier, and to make protozoa or metazoa prey on the bacteria in the second aerobic tank. By using the above method, it is possible to effectively reduce the non-aggregating SS derived from the anaerobic treatment, particularly by subjecting the organic wastewater to anaerobically treatment and then aerobic treatment. Furthermore, in a biological treatment method and apparatus for organic wastewater in which the organic wastewater is anaerobically treated and then aerobically treated, and then the bacteria are preyed on by protozoa or metazoa in the second aerobic tank, the non-aggregating SS derived from the anaerobic treatment can be further effectively reduced by making the protozoa or metazoa dominant in the second aerobic tank.

(Methods for reducing sludge)
The application example of the MABR system shown below is effective for improving the efficiency of wastewater treatment by reducing excess sludge generated from biological treatment and sludge generated in solid-liquid separation processes such as sedimentation, coagulation sedimentation, pressure flotation, membrane separation, and filtration. Efficiency means, for example, improving, maintaining, and stabilizing wastewater treatment performance.

A wastewater treatment device equipped with a biological treatment means for reducing selenium oxides present in selenium-containing wastewater to Se by anaerobic biological treatment to insolubilize and remove the selenium oxides, characterized in that the biological treatment means has a plurality of biological treatment steps in which biological treatments including a MABR method, aerobic treatment, and anaerobic treatment are sequentially performed. The selenium oxides are preferably _SeO3 ^2- and/or _SeO4 ^2- . Use of the device is particularly effective in improving the efficiency and stabilizing the reduction reaction of selenium oxides when selenium oxides present in selenium-containing wastewater are reduced to elemental selenium by anaerobic biological treatment to insolubilize the selenium oxides.

A biological treatment method including an anaerobic biological treatment step in which wastewater containing organic matter is fermented under anaerobism to produce methane, the biological treatment step including anaerobic biological treatment in the presence of a gel-like carrier at a water temperature of less than 50°C, preferably less than 35°C, and characterized in that an oxygen-permeable membrane is used in the anaerobic biological treatment step or in steps before or after the anaerobic biological treatment step. By using the above method, an anaerobic biological treatment method can be effectively obtained in which wastewater containing organic matter is fermented under anaerobism under a high load and in a stable manner to produce methane, even under low water temperature conditions.

A waste treatment device that is provided with a treatment section having a biological treatment tank that biologically treats oil-containing organic waste with methanogens, and further includes a solid-liquid separation section that separates the water contained in the biological treatment tank into solid and liquid to obtain separated water having a higher water content than the water contained in the biological treatment tank and a concentrate having a lower water content than the water contained in the biological treatment tank, a water transfer section that transfers the water contained in the biological treatment tank from the biological treatment tank to the solid-liquid separation section, and a separated water transfer section that transfers the separated water to the biological treatment tank. A gas supply may be used for at least a part of the waste treatment device.

In a biomass processing method comprising a pretreatment step of producing fermentation components from the polysaccharides in a processing material obtained by mixing biomass containing polysaccharides, ruminal microorganisms derived from ruminants, and at least one of a methane fermentation separation liquid separated by solid-liquid separation from a methane fermentation residue that has undergone a methane fermentation process, and an ethanol fermentation separation liquid separated by solid-liquid separation from an ethanol fermentation residue that has undergone an ethanol fermentation process, a gas supplier may be used for at least a portion of the processing material. In addition, in a wastewater treatment method comprising a first treatment step of biologically treating organic wastewater with activated sludge, and a second treatment step of subjecting fermentation components produced from polysaccharides by ruminant-derived ruminant microorganisms to methane fermentation treatment, the second treatment step comprising a pretreatment step of producing the fermentation components in a treatment target obtained by mixing biomass containing the polysaccharides, the rumen microorganisms, and at least one of a methane fermentation separate liquid separated by solid-liquid separation from a methane fermentation residue that has undergone the methane fermentation treatment and an ethanol fermentation separate liquid separated by solid-liquid separation from an ethanol fermentation residue that has undergone the ethanol fermentation treatment, and a methane fermentation step of subjecting at least a portion of the treatment target containing the fermentation components to the methane fermentation treatment, and in which the methane fermentation treatment in the second treatment step is performed on a portion of excess sludge generated as a result of the biological treatment in the first treatment step, a gas supplier may be used for at least a portion of the treatment target. Furthermore, the wastewater treatment equipment includes a first treatment section that biologically treats organic wastewater with activated sludge, and a second treatment section that performs methane fermentation treatment on fermentation components produced from polysaccharides by ruminant-derived ruminal microorganisms, and the second treatment section has a pretreatment section that produces the fermentation components in a treatment target that is a mixture of biomass containing the polysaccharides, the ruminal microorganisms, and at least one of a methane fermentation separation liquid separated by solid-liquid separation from a methane fermentation residue that has undergone the methane fermentation treatment, and an ethanol fermentation separation liquid separated by solid-liquid separation from an ethanol fermentation residue that has undergone the ethanol fermentation treatment, and a methane fermentation section that performs the methane fermentation treatment on at least a portion of the treatment target that contains the fermentation components. A gas supplier may be used in at least a portion of the wastewater treatment equipment, which is configured to supply a portion of the excess sludge generated by the biological treatment in the first treatment section to the methane fermentation section, and perform the methane fermentation treatment on the supplied excess sludge in the methane fermentation section.

A biological treatment method for organic wastewater, comprising the steps of: introducing organic wastewater into a first biological treatment tank having a BOD volume load of 1 kg/ ^m3 /day or more among aerobic biological treatment tanks arranged in two or more stages; passing the first biological treatment water containing dispersed bacteria through the first biological treatment tank for biological treatment by passing the first biological treatment water through a second or subsequent biological treatment tank having a soluble BOD sludge load of 0.25 to 0.50 kg-BOD/kg-MLSS/day; providing carriers for holding microorganisms in the second or subsequent biological treatment tanks with a filling rate of 0.5 to 40%; extracting a portion of the sludge from the second or subsequent biological treatment tanks, treating it in an anoxic tank, and returning it to the second or subsequent biological treatment tanks; and including an oxygen permeable membrane in at least one of the biological treatment tanks. The carrier is preferably a fixed bed plate carrier made of polyurethane foam. By using the above method, it is possible to effectively improve the quality of treated water by prioritizing filter-feeding micro-animals, particularly in a multi-stage activated sludge process that utilizes the feeding action of micro-animals, while improving the treatment efficiency and reducing the volume of sludge.

(Method for starting up a biological treatment device)
The application examples of the MABR system shown below are effective in making wastewater treatment more efficient. Efficiency means, for example, improving, maintaining, and stabilizing wastewater treatment performance.

A method for treating organic wastewater, comprising a process for biologically treating organic wastewater under anaerobic conditions in a fluidized bed reactor, the process being characterized in that, when starting up the biological treatment, a carrier having non-anaerobic or anaerobic microorganisms attached thereto as a biofilm is introduced into the reactor, and further comprising an MABR tank. Alternatively, a method for treating organic wastewater, comprising a process for biologically treating organic wastewater in a MABR tank, the process being characterized in that, when starting up the biological treatment, a carrier having non-anaerobic or anaerobic microorganisms attached thereto as a biofilm or an oxygen-permeable membrane is introduced into the MABR tank. By using these methods, it is possible to provide a method for treating organic wastewater that can particularly suppress the lengthening of the start-up period of biological treatment.

A wastewater treatment method for treating wastewater containing organic matter by the MABR method, characterized in that the method is operated while a carrier is present in a biological reactor. By using the method, it is possible to effectively obtain a wastewater treatment method and a wastewater treatment device that enable stable operation by suppressing clogging of the oxygen permeable membrane. The carrier is preferably in the form of a sponge with a density of 35 kg/m3 or ^more .

A method for treating water containing a nitrogen source such as organic nitrogen or ammonia by passing the water through a nitrification tank to decompose the nitrogen source, comprising: retaining a primary biofilm body in the nitrification tank, which is a self-granulated denitrifying bacterium that performs a denitrification reaction using methanogen granules as a nucleus, ammonia nitrogen as an electron donor, and nitrite nitrogen as an electron acceptor; forming a biofilm double structure in which the surface of the primary biofilm body is covered with ammonia oxidizing bacteria in the nitrification tank; and including an oxygen-permeable membrane. By using the method described above, it is possible to effectively use ANAMMOX bacteria in the nitrification and denitrification treatment of ammonia-containing water, significantly reduce the treatment cost, and stably obtain high-quality treated water. It is also preferable to retain the primary biofilm body in the oxygen-permeable membrane.
A water treatment management method for managing the treatment performance of a water treatment process in which nitrification and denitrification are performed in the same tank, the water treatment process using multiple types of bacteria to remove nitrogen components from the water to be treated that is supplied to a water treatment tank, and the water treatment management method includes a selection step for selecting, from a group consisting of ammonia oxidizing bacteria, nitrite oxidizing bacteria, nitrate reducing bacteria, nitrite reducing bacteria and nitrous oxide reducing bacteria, a bacterium with the highest coefficient of determination based on the relationship between the number of a single bacterium and the total nitrogen load, as an indicator bacterium that serves as an indicator of treatment performance, a measurement step for measuring the number of indicator bacteria in the water treatment tank, and a retention step for retaining a predetermined number or more of indicator bacteria in the water treatment tank, and at least a gas supplier may be used for part of the water treatment management method.

A method for operating a wastewater treatment device using a semi-batch reaction tank in which an operating cycle having an inflow process for inflowing organic matter-containing wastewater, a biological treatment process for biologically treating the substances to be treated in the organic matter-containing wastewater with microbial sludge, a sedimentation process for settling the microbial sludge, and a discharge process for discharging the biologically treated biologically treated water is repeated to grow microorganisms or form granules, the operating cycle having a first operating cycle in which the biological treatment process is performed with a first sludge load, and a second operating cycle in which the biological treatment process is performed with a second sludge load after the first operating cycle, the first sludge load is a sludge load set so that the soluble BOD concentration in the semi-batch reaction tank at the end of the biological treatment process of the first operating cycle does not fall below a threshold value, and the second sludge load is a sludge load set so that the soluble BOD concentration in the semi-batch reaction tank at the end of the biological treatment process of the second operating cycle is below a threshold value. By using the above method, it is possible to effectively grow microorganisms or form granules.

A method for cultivating microorganisms or forming granules using a semi-batch reaction tank in which a step of introducing organic wastewater into the reaction tank, a biological treatment step of biologically treating the target substances in the organic wastewater with microbial sludge, a settling step of settling the microbial sludge, and a discharge step of discharging the biologically treated biologically treated water are repeated to cultivate microorganisms or form granules, in which the biological treatment step monitors the pH in the semi-batch reaction tank, adjusts the time of the biological treatment step based on information about the monitored pH, and includes an oxygen-permeable membrane inside the biological treatment step. By using the above method, it is possible to provide a method for cultivating microorganisms or a method for forming granules that can form good granules even if the BOD concentration of the organic wastewater fluctuates, and an apparatus for the same.

A wastewater treatment method comprising a nitrification step of aerobically biologically treating nitrogen-containing wastewater in a nitrification reaction tank, a denitrification step of anaerobically biologically treating the wastewater in a denitrification reaction tank, a solid-liquid separation step of separating wastewater discharged from the nitrification step and the denitrification step into biological sludge and treated water, and a sludge return step of returning the separated sludge to the nitrification step or the denitrification step, the method comprising, at the start-up of biological treatment, a step of feeding granules having nitrification ability into the wastewater in the nitrification step, and a step of feeding only denitrification sludge that has not been granulated into the wastewater in the denitrification step, and a step of producing nitrification-denitrification granules having nitrification ability and denitrification ability by the granules having nitrification ability and the denitrifying bacteria in the denitrification reaction tank while returning sludge in the sludge return step, and characterized in that at least one of the tanks in which the nitrification step, the denitrification step, and the solid-liquid separation step are performed includes an oxygen-permeable membrane. It is preferable that the oxygen-permeable membrane is included in at least the nitrification process. The nitrification process, denitrification process, and solid-liquid separation process may be performed in the same tank in any combination of two or more of the processes. By using the above method, it is possible to effectively provide a wastewater treatment method and treatment device that can improve the settling property of sludge and increase the treatment speed (load), particularly in wastewater treatment in which nitrification and denitrification are performed using biological sludge.

This method of biologically treating organic wastewater is characterized in that the organic wastewater is nitrified and denitrified using a gas supplier, and then the sludge generated by the nitrification and denitrification processes is solubilized, making it possible to effectively treat the organic wastewater.

A biological treatment apparatus comprising: a biological treatment tank that contains an oxygen-permeable membrane or a carrier that holds microorganisms and treats organic matter-containing water; and an iron salt adding means that adds iron salt to the biological treatment tank when the thickening of the carrier is confirmed, the iron salt adding means adding the iron salt to the biological treatment tank so that the MLVSS/MLSS (%) of the biological sludge attached to the carrier after the thickening of the carrier is confirmed is reduced by 10 percentage points or more. The biological treatment tank is preferably a fluidized bed type biological treatment tank that includes an oxygen-permeable membrane. By using the apparatus, it is possible to effectively provide a biological treatment apparatus and a biological treatment method that are particularly capable of improving the thickening of the carrier.

A method for forming aerobic granules, in which raw water containing organic matter and iron ions at 0.1 mg-Fe/L or more is continuously introduced from the bottom of a reaction tank and brought into contact with microorganisms in the reaction tank, the raw water is adjusted to have a C/N ratio of 7 or less before being introduced into the reaction tank, and the granules are formed in the reaction tank under aerobic conditions in the presence of nitrifying bacteria. By using the above method, it is possible to effectively provide a method for forming aerobic granules that can stably form granules under aerobic conditions using a continuous water flow system.

In a method for treating digested sludge effluent, the method comprises: a supply step for supplying digested sludge effluent and concentrated, dehydrated separated liquid of primary sedimentation raw sludge to a treatment tank containing aerobic granules; a concentration measurement step for measuring the nitrogen concentration of the digested sludge effluent and the carbon concentration of the concentrated, dehydrated separated liquid of the primary sedimentation raw sludge; and a control step for controlling the amount of concentrated, dehydrated separated liquid of the primary sedimentation raw sludge supplied so that the carbon concentration/nitrogen concentration is within a predetermined range. A gas supplier may be used for at least a part of the method. In addition, in a digested sludge eluate treatment device having a treatment tank containing aerobic granules, a supply line for supplying digested sludge eluate and concentrated dehydrated separation liquid of primary sedimentation raw sludge to the treatment tank, a concentration measuring means for measuring the nitrogen concentration of the digested sludge eluate and the carbon concentration of the concentrated dehydrated separation liquid of the primary sedimentation raw sludge, respectively, and a control means for controlling the supply amount of the concentrated dehydrated separation liquid of the primary sedimentation raw sludge so that the carbon concentration/nitrogen concentration is within a predetermined range, a gas supply may be used for at least a part of the digested sludge eluate treatment device.

(Method of cleaning oxygen-permeable membrane)
The application example of the MABR method shown below is effective in removing biofilms, garbage, impurities, SS, etc. attached to the oxygen permeable membrane, and improving the efficiency of wastewater treatment. For example, efficiency means improving, maintaining, stabilizing, etc. the wastewater treatment performance.

If excessive biofilm or solid matter accumulates on the surface of the oxygen-permeable membrane after long-term use, causing a decline in treatment performance, the oxygen-permeable membrane must be cleaned. When cleaning, it is effective to pull the oxygen-permeable membrane as a unit out of the water being treated and remove the deposits.

A method for removing BOD components by filling an oxygen-permeable membrane or filler with aerobic microorganisms on its surface (hereinafter referred to as the filler layer) and introducing water to be treated that contains BOD components from the bottom or top of the filler layer, the method being characterized in that the tank is divided into multiple chambers with approximately equal cross-sectional areas, the tank is divided so that the total treatment flow rate of the multiple divided chambers is approximately equal to the cleaning flow rate of each chamber, and a water to be treated supply pipe and an air supply pipe are provided at the bottom or top of each chamber.

An aerobic biological treatment device comprising: an MABR tank filled with oxygen-permeable membranes with aerobic microorganisms growing on the surface; raw water containing organic matter and oxygen-containing gas are introduced into the oxygen-permeable membrane layer to remove organic matter from the raw water by biological treatment; a sedimentation tank that removes turbidity from the treated water in the MABR tank by sedimentation; and a cleaning pump that directly extracts the supernatant water in the sedimentation tank from the tank and supplies the extracted supernatant water to the bottom of the MABR tank. When the oxygen-permeable membrane layer in the MABR tank becomes clogged, the cleaning pump extracts the supernatant water in the sedimentation tank and supplies it to the bottom of the MABR tank to clean the oxygen-permeable membrane layer, and the entire amount of cleaning wastewater discharged from the MABR tank during cleaning is introduced directly into the sedimentation tank for treatment.

A method for cleaning an oxygen-permeable membrane in a biological treatment device in which an oxygen-permeable membrane layer made of an oxygen-permeable membrane with a biofilm attached thereto is provided in a treatment tank, and raw water is passed through the oxygen-permeable membrane layer in a downward flow to treat BOD and other substances in the raw water using microorganisms in the biofilm. This method is characterized by simultaneously draining water from the bottom of the tank and supplying cleaning air to the bottom of the tank, disturbing the gradually descending liquid surface in the tank with the cleaning air, and peeling off the biofilm attached to the oxygen-permeable membrane.

(How to use oxygen permeable membranes to save space)
The application example of the MABR method shown below is an example of a MABR tank that aims to reduce the tank volume and installation space of the MABR tank, and is effective in making wastewater treatment more efficient. Efficiency means, for example, improving, maintaining, and stabilizing wastewater treatment performance.

In a MABR tank, when the oxygen-permeable membrane is installed at the top of the tank and there is space at the bottom, a water flow is generated at the bottom of the MABR tank and the water to be treated is stirred, improving the contact efficiency between the water to be treated and the oxygen-permeable membrane. By using the above method, it is possible to effectively reduce the installation space and improve the efficiency of wastewater treatment. A submersible agitator is preferably installed as a method for generating a water flow. As another example, for example, oxygen-permeable membranes with a long vertical length are installed in the oxygen-permeable membranes in the area where the load is large, such as the inlet side of the water to be treated, and oxygen-permeable membranes with a short vertical length are installed on the side where the load is small, thereby reducing the number of oxygen-permeable membranes, reducing costs and reducing the installation effort. The area where the load is large and the area where the load is small may each be a separate MABR tank.

The MABR tank is characterized by having an oxygen-permeable membrane installed in the settling tank, a submerged weir installed at the inflow of the water to be treated, and an overflow weir installed at the outflow of the water to be treated. By using the above tank, organic matter can be treated even in the settling tank, making it possible to improve the efficiency of treatment in the entire wastewater treatment equipment. It is preferable to install the oxygen-permeable membrane so as not to interfere with the downstream flow of the water to be treated. Specifically, it is preferable to install the oxygen-permeable membrane parallel to the downstream direction. In addition, when the wastewater treatment equipment has a first settling tank and a final settling tank, it is preferable to install the oxygen-permeable membrane in the first settling tank, which has a large load, but it is also possible to install oxygen-permeable membranes in both settling tanks.

A flow adjustment tank with an oxygen-permeable membrane installed. By using this tank, the flow adjustment tank can be made aerobic, and odors generated from the flow adjustment tank can be suppressed and sludge can be reduced. At the same time, there is no need for blower power to supply air to the aeration device, which saves energy. Furthermore, when an aeration device is used, aeration efficiency decreases when the water level in the flow adjustment tank is low, but by using an oxygen-permeable membrane, the effect of the water level can be reduced, and the above effects can be obtained more effectively than with an aeration device.

In a biological treatment apparatus in which a casing that houses gas supply units in multiple vertical tiers is submerged in a reaction tank, an auxiliary air diffuser is installed between the gas supply units submerged in multiple vertical tiers, enabling effective air diffusion.

A gas supply body further provided with an air diffusion mechanism that generates air bubbles at the lower end side of the gas supply body, the lower fixed member of the gas supply body further comprising a gas storage chamber and an air bubble passage from the gas storage chamber to the upper surface side of the fixed part, and the gas supply body characterized in that the air diffusion mechanism is provided so that gas is stored in the gas storage chamber and the stored gas floats through the air bubble passage to generate air bubbles above the fixed part, can effectively diffuse air.

A gas supply body equipped with a diffuser member for generating air bubbles at the lower end of the gas supply body, the diffuser member having a hollow body arranged at the lower end of the gas supply body and having an air diffusion hole opened on its upper surface side, configured so that gas is supplied to the hollow body from a tube connected to the hollow body to generate air bubbles from the air diffusion hole, and the air diffusion hole is opened upward above the fixing part of the lower fixing member, so that effective air diffusion can be performed with this gas supply body.

A gas supply body used by immersing in water that is equipped with an air diffusion mechanism capable of diffusing gas into the gas supply body, the air diffusion mechanism comprising a tubular body that is fixed at both ends to an upper fixing member and a lower fixing member and extends between the upper fixing member and the lower fixing member, and the circumferential surface of the tubular body is formed with air diffusion holes that can diffuse the gas in the tube into the gas supply body, can effectively diffuse air.

In a biological treatment method in which the water to be treated is stored in a biological treatment tank, and air bubbles are released from an air diffuser into the water in the treatment tank to diffuse the water in the tank in the direction of the air bubbles, forming a circulating flow in the biological treatment tank while carrying out biological treatment. The biological treatment method is characterized in that a circulating flow step is carried out in which air bubbles are released in the direction of the circulating flow to diffuse the air, and a circulating flow change step is carried out after the circulating flow step in which air bubbles are released in a direction opposite to the circulating flow formed in the biological treatment tank to cause the water in the tank to flow in a direction different from the circulating flow to form a new circulating flow. In this biological treatment method, a gas supply may be used for at least a part of the circulating flow. The air diffuser may be installed on the bottom or side of the treatment tank. It may also be installed in a ring shape. Furthermore, the air diffuser may be configured to be movable.

A method for operating an organic wastewater treatment facility comprising a biological treatment tank for decomposing organic matter in raw water and a final settling tank for settling and removing sludge from the biologically treated water in the biological treatment tank, the method being characterized in that the amount of aeration is adjusted so that the dissolved oxygen concentration in the biological treatment tank is 1 mg/L or less, thereby reducing the amount of sludge flowing out from the final settling tank. A gas supply may be used in at least a portion of the biological treatment tank.

(Other application methods)
The application examples of the MABR system shown below are effective in making wastewater treatment more efficient. Efficiency means, for example, improving, maintaining, and stabilizing wastewater treatment performance.

A method for treating organic wastewater comprising a biological treatment process for biologically treating organic wastewater in the presence of a carrier, a solid-liquid separation process for separating wastewater containing suspended solids into sludge and treated water, a solubilization process for solubilizing the sludge, and a solubilized sludge supply process for supplying the solubilized sludge to the biological treatment process, characterized in that an oxygen-permeable membrane is used in the biological treatment process or the solubilization process. By using the method, it is possible to effectively provide a method and treatment device for treating organic wastewater that can reduce the amount of excess sludge.

A method for treating glycerin-containing wastewater, comprising a primary treatment step in which glycerin-containing wastewater is treated with a microorganism belonging to the genus Aurantiochytrium and capable of producing fatty acids having 14 or more carbon atoms (hereinafter referred to as "Aurantiochytrium microorganism") and then subjected to solid-liquid separation, and a secondary treatment step in which organic matter remaining in the treated water from the primary treatment step is removed, characterized in that an oxygen-permeable membrane is used in at least one of the primary and secondary treatment steps. By using the above method, it is possible to effectively provide a method and apparatus for treating glycerin-containing wastewater, such as crude glycerin produced as a by-product in a biodiesel production process, which is a valuable product-producing treatment method and treatment device.

A wastewater treatment device characterized by having an iron salt reaction means for adding and mixing a trivalent iron salt to wastewater containing organic matter and hydroxylamine or its salt in an amount equal to or twice the theoretical amount for oxidizing hydroxylamine, thereby oxidizing the hydroxylamine in the wastewater and reducing the trivalent iron to divalent iron, a hydrogen peroxide reaction means for adding and mixing hydrogen peroxide to the wastewater after the iron salt has been added and reacted with the hydroxylamine, and decomposing the organic matter by a Fenton oxidation reaction using the reduced divalent iron, and a biological treatment means for biologically treating the wastewater after the hydrogen peroxide has been added and mixed in a MABR tank. By using the above device, it is possible to efficiently treat wastewater containing reducing agents and difficult-to-decompose organic matter.

A biological treatment method for oil-containing wastewater in which a concentration ratio of calcium to normal hexane extracts is 0.02 or more is biologically treated using an MABR tank, the biological treatment method for oil-containing wastewater being characterized in that an iron salt is added to the oil-containing wastewater so that the concentration ratio of iron to calcium in the oil-containing wastewater is 0.1 or more. By using the above method, it is possible to effectively provide a biological treatment method and biological treatment device for oil-containing wastewater that is capable of decomposing the oils and fats in the oil-containing wastewater and suppressing the generation of oil balls.

A biological treatment device for oil-containing wastewater, comprising: a treatment tank unit having at least a first treatment tank and a second treatment tank for aerobic biological treatment of oil-containing wastewater; and an iron salt supplying means for supplying an iron salt to the first treatment tank, wherein the iron salt supplying means supplies the first treatment tank with an iron salt such that the total amount of iron per unit volume of the oil-containing wastewater is 1.0× ^10-3 or more in terms of a weight ratio of iron to a load amount of normal hexane extracts per unit volume of the oil-containing wastewater, and at least one of the first treatment tank and the second treatment tank is an MABR tank. By using the device, it is possible to effectively provide a biological treatment device and a biological treatment method for oil-containing wastewater that can efficiently biologically treat oils and fats in the oil-containing wastewater.

A biological treatment method for oil-containing wastewater, comprising a biological treatment step of biologically treating oil-containing wastewater in the presence of a sponge carrier, the sponge carrier having a cell count in the range of 8-20 cells/25 mm, and the biological treatment step being an MABR system. By using the method, it is possible to effectively provide a biological treatment method and biological treatment device for oil-containing wastewater that can stably biologically treat the oils and fats in the oil-containing wastewater. The sponge carrier may be supported on the surface of an oxygen-permeable membrane included in a biological treatment tank of the MABR system.

A method for purifying contaminated soil and groundwater by using microorganisms to purify contaminated soil contaminated with volatile organic chlorine compounds and contaminated groundwater flowing through the contaminated soil, characterized in that a carrier having an oxygen-permeable membrane and pores, and nutrients for the microorganisms, are added to a well installed in the contaminated groundwater flowing through the contaminated soil. By using the method, it is possible to effectively provide a method for purifying contaminated soil and groundwater, a purification promoter, and a method for producing the same, which can efficiently decompose the contaminants, volatile organic chlorine compounds.

The gas supply may be used as a water treatment device that includes a flocculation section that obtains flocculated water by mixing the water to be treated containing suspended solids with a flocculant, a tank that obtains separated water and sediment from the flocculated water by sedimentation separation, a gas supply body disposed in the tank, an aeration section disposed in the tank that disperses aeration into the separated water, and a partition plate that divides the tank into a sedimentation region where the separated water and the sediment are obtained from the flocculated water by sedimentation separation and an aeration region where the aeration section diffuses aeration into the separated water, the lower plate being inclined relative to the horizontal, and a discharge section that discharges the suspended solids flowing down along the lower plate from the aeration region to the sedimentation region.

The membrane separation activated sludge treatment device enables effective biological treatment by comprising a biological treatment section which mixes the flocculated sludge body produced by the biological flocculation means which biologically flocculates activated sludge to produce flocculated sludge body with wastewater to produce mixed water and biologically treats the mixed water to obtain sludge-containing biologically treated water, and a purified treated water production section which has a membrane unit which performs membrane filtration and produces purified treated water as permeate from the sludge-containing biologically treated water by membrane filtration, and the biological flocculation means flocculates the activated sludge with a gas supply and separates the flocculated sludge body from the gas supply.

A method for treating exhaust gas in an exhaust gas treatment facility of an incineration plant equipped with a fluidized bed incinerator and an exhaust gas treatment facility for treating exhaust gas generated by incineration of waste in the fluidized bed incinerator, comprising: a dust collection process for recovering fly ash contained in the exhaust gas in a dust collection section while discharging the exhaust gas to a temperature reducing section; a fly ash supply process for supplying only fly ash present upstream of the temperature reducing section in the flow direction of the exhaust gas, including the fly ash recovered in the dust collection process, to a cleaning section; a plant wastewater supply process for supplying plant wastewater generated in the incineration plant to the cleaning section; The method for treating exhaust gas from a fluidized bed incinerator includes a washing process in which the fly ash supplied in the fly ash supply process is washed and the chlorides in the fly ash are dissolved in a mixed water of the washing water and the supplied plant wastewater to produce washed ash and chloride-containing washed wastewater, a temperature reduction process in which the washed wastewater produced in the washing process is supplied to the temperature reduction section to cool the exhaust gas in the temperature reduction section and evaporate the washed wastewater, and a chloride recovery process in which the chloride-containing fly ash of the washed wastewater evaporated in the washing wastewater supply process is recovered in a filter section, and a gas supply may be used in at least a part of the processes.

In a wastewater treatment method including a first treatment step of culturing microalgae in wastewater and a second treatment step of treating wastewater containing the first treated water after culturing the microalgae in the first treatment step, the second treatment step may include a gas supplier, and oxygen may be supplied from the gas supplier to perform aerobic treatment.

(Example)
Examples will be described below.
Example 1
The gas supplier 10 of Example 1 is the same as the gas supplier 10 of the first embodiment, except that the shape of the distribution section 62a is different from that of the distribution section 62 of the first embodiment in Fig. 4. The cross section of the distribution section 62 of the first embodiment in Fig. 4 is arc-shaped, whereas the cross section of the distribution section 62a of Example 1 is rectangular.
The gas supply body 10 of Example 1 has a width of 1 m, a length of 4 m, and an effective area of 8 m ² (on both sides).
The gas sending source section 61 in the first embodiment is two polyethylene tubes of φ4*6 mm. The distribution section 62a is a resin member having a width A of 3 mm. The throttle section 63a is a resin member having a throttle width B of 0.5 mm. The hollow plate member of the gas sending layer 12 is a resin hollow plate member having a length of 4 m in the first direction and a length of 1 m in the first direction and a direction perpendicular to the first direction.

Example 2
The gas supplier 10 of Example 2 has the same configuration as the gas supplier 10 of Example 1, except for the configuration of the throttle section 63b and the width of the gas delivery layer 12. As shown in FIG. 8, in Example 2, the gas delivery layer 12 and the throttle section 63b are integrated. In other words, the throttle section 63b is an end of the gas delivery layer 12. That is, in Example 2, the width of the gas delivery layer 12 is narrowed to restrict the flow of gas from the distribution section 62b. The distribution section 62b has a width A of 5 mm. The throttle width B of the throttle section 63b is 2.7 mm. The distribution section 62b and the throttle section 63b are made of resin.

(Comparative Example 1)
The gas supplier 10 of Comparative Example 1 has the same structure as the gas supplier 10 of Example 1, except for the absence of a throttle section and the width of the distribution section 62c, as shown in Fig. 9. The distribution section 62c and the gas delivery layer 12 of Comparative Example 1 are made of resin. The width A of the distribution section 62c is 0.8 mm. If the width of the throttle section is the width B of the gas delivery layer 12 as shown in Fig. 9, it is 2.7 mm.

(Comparative Example 2)
As shown in Fig. 10, the gas supplier 10 of Comparative Example 2 has the same configuration as the gas supplier 10 of Example 1, except for the absence of a throttling portion and the width of the distribution section 62d. The distribution section 62d of Comparative Example 2 is narrow in width like the distribution section 62c of Comparative Example 1, but the direction in which the width is narrow is different between the two. The distribution section 62d and the gas delivery layer 12 of Comparative Example 2 are made of resin. The width A of the distribution section 62d is 2 mm. If the width of the throttling portion is the width B of the gas delivery layer 12 as shown in Fig. 10, it is 9 mm.

(Method of measuring length A of minimum inner diameter part of distribution part 62)
The length A of the smallest part of the inner diameter of the distribution section 62 was measured using a ruler or a vernier caliper. The smallest part refers to the diameter in the case of a perfect circle, the short line in the case of an ellipse, and the short side in the case of a rectangle.

(Method of measuring length B of the narrowed width of the narrowed portion 63)
The length B of the drawn width of the drawn portion 63 was measured using a ruler, calipers, or a micrometer. When direct measurement was difficult, a sheet of known thickness was inserted into the drawn portion 63, and the thickness of the sheet with the same dimension was determined as the drawn width.

(Method of measuring oxygen-containing gas supply rate per effective area of gas supplier 10)
The oxygen-containing gas supply rate per effective area of the gas supply body 10 is calculated from the flow rate of the oxygen-containing gas supplied to the gas delivery layer 12. The flow rate of the oxygen-containing gas was measured using a mass flow meter. In this test, air with an oxygen content of 21% was used as the oxygen-containing gas.

(Method of measuring pressure loss in gas supplier 10)
A pressure gauge was installed at the inlet of the gas supplier 10, i.e., the starting point of the air supply section 60, to measure the pressure. In this test, the outlet of the gas supplier 10 was set to 0 kPa because it was open to atmospheric pressure.

(Method for confirming the proportion of gas sent to the entire gas supplier 10)
A gas leak checker was applied to the gas outlet of the gas delivery layer 12, and it was visually determined whether gas was being supplied. The percentage of the gas supply outlets to which gas was being supplied with respect to the total number of gas outlets was calculated as the gas supply ratio (%) to the entire gas supplier 10. As a more detailed method, an air flow meter may be installed at the gas outlet of each gas delivery layer 12 to measure the supply flow rate.

The measurement results for Examples 1 and 2 and Comparative Examples 1 and 2 are summarized in Table 1 below.

表１から理解されるように、絞り部６３を有する実施例１，２の気体供給体１０は、気体供給体全体への送気割合が１００％であるのに対して、絞り部６３を有さない比較例１，２の気体供給体１０は、気体供給体全体への送気割合が１０～１５％しかない。つまり、実施例１，２の気体供給体１０は、気体送出層１２で分割された空間に、適切に気体が分配されているのに対して、比較例１，２の気体供給体１０は、気体送出層１２で分割された空間に、適切に気体が分配されていないことがわかる。

As can be seen from Table 1, the gas suppliers 10 of Examples 1 and 2 having the throttle portion 63 have a gas supply ratio of 100% to the entire gas supplier, whereas the gas suppliers 10 of Comparative Examples 1 and 2 not having the throttle portion 63 have a gas supply ratio of only 10 to 15% to the entire gas supplier. In other words, it can be seen that the gas suppliers 10 of Examples 1 and 2 properly distribute gas to the spaces divided by the gas delivery layer 12, whereas the gas suppliers 10 of Comparative Examples 1 and 2 do not properly distribute gas to the spaces divided by the gas delivery layer 12.

REFERENCE SIGNS LIST 10 Gas supplier 12 Gas supply layer 21 Waterproof air-permeable membrane 51 Wastewater treatment tank 52 Supply unit 53 Gas supply source 60 Air supply section 61 Air supply source section 62 Distribution section 63 Throttle section 65 Space serving as a gas supply path 100 Wastewater treatment device S Gas flow path

Claims (8)

A gas supplier used in a wastewater treatment device that purifies wastewater by utilizing the action of microorganisms,
a sheet laminate having an exterior immersed in wastewater and an interior supplied with gas;
a gas-transporting layer that divides the space inside the sheet stack;
an air supply unit disposed inside the sheet stack and supplying gas to a space inside the sheet stack;
Including,
The air supply unit includes:
a gas supply source unit that supplies gas from a gas supply source;
a distribution section that supplies the gas from the gas supply source section to a space divided by the gas supply layer;
a throttle section between the distribution section and the gas delivery layer for restricting the amount of gas supplied to the space divided by the gas delivery layer;
Including,
Gas supply. The gas is supplied to the space divided by the gas delivery layer from bottom to top.
The gas supplier according to claim 1 . The distribution section has a minimum inner diameter (A) of 1 to 200 mm.
The gas supplier according to claim 1 or 2. The narrowing portion has a narrowing width (B) of 0.01 to 8 mm.
The gas supplier according to any one of claims 1 to 3. The ratio (B/A) of the minimum inner diameter portion (A) of the distribution portion to the narrowing width (B) of the narrowing portion is 0.0001 or more and 0.6 or less.
The gas supplier according to any one of claims 1 to 4. Under the condition that the supply of gas to the entire gas supply body is achieved, the ratio (C/D) of the oxygen-containing gas supply rate (g/ ^m2 /day) per effective area of the gas supply body (C) to the pressure loss (kPa) (D) in the gas delivery layer is 210 or less.
The gas supplier according to any one of claims 1 to 5. A gas supply system comprising a plurality of gas supply bodies according to any one of claims 1 to 6.
Supply unit. A wastewater treatment device comprising the gas supplier according to any one of claims 1 to 6, or the supplier unit according to claim 7.

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