Method for treating organic wastewater, treatment device for organic wastewater, and chemical agent for removing recalcitrant organic matter and color components from organic wastewater.

Abstract

To provide a method of treating organic wastewater, capable of stably and efficiently carrying out biological treatment and efficiently removing a hardly decomposable organic substance and a chromaticity component present in the organic wastewater, a device of treating the organic wastewater, and a chemical for removing the hardly decomposable organic substance and the chromaticity component present in the organic wastewater.SOLUTION: The method of treating organic wastewater, comprises: adding a bioactive agent including an iron ion and a calcium ion to organic wastewater including a hardly decomposable organic substance and a chromaticity component; feeding a fluid carrier into the organic wastewater added with a bioactive agent; and causing a microorganism to adhere to the fluid carrier to biologically treat the organic wastewater, thereby removing the hardly decomposable organic substance and the chromaticity component present in the organic waste water.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for treating organic wastewater, an apparatus for treating organic wastewater, and an agent for removing recalcitrant organic matter and color components from organic wastewater. [Background technology]

[0002] Organic wastewater is discharged from factories and businesses of all types. In particular, wastewater discharged from soft drink manufacturers during the production of tea or coffee products is known to contain large amounts of recalcitrant organic matter and color components.

[0003] Common methods for treating organic wastewater include pretreatment (primary treatment), biological treatment (secondary treatment), and advanced treatment (tertiary treatment). Pretreatment is the process of removing impurities from the wastewater and includes physicochemical treatment methods (screening, pressurized flotation, coagulation and sedimentation, natural solid-liquid separation, etc.). After pretreatment, the wastewater is subjected to biological treatment, and if a large amount of nutrients and other components that could not be removed by biological treatment remain, further advanced treatment is performed. The treated water is discharged outside the system, but residues and excess sludge generated in each process require separate treatment.

[0004] In particular, in the case of organic wastewater containing high-molecular-weight, recalcitrant organic substances and chromatic components, these components are difficult to remove by biological treatment, and advanced treatment is required. However, since a large amount of recalcitrant organic substances and chromatic components remain in the treated water after biological treatment, there are challenges such as an increase in treatment processes and equipment, and an increase in chemical costs.

[0005] For example, Japanese Patent Publication No. 2021-20138 (Patent Document 1) describes a liquid wastewater biological treatment accelerator for promoting starch decomposition by Bacillus bacteria in a biological treatment tank, comprising at least one selected from calcium ions or iron ions. Specifically, it describes promoting starch decomposition by specific Bacillus bacteria in a biological treatment tank during the treatment of wastewater containing at least starch, and preventing an increase in sludge generation due to the accumulation of the agent itself and preventing pipe blockage.

[0006] Japanese Patent Application Laid-Open No. 2018-153713 (Patent Document 2) describes a bioactivator mainly composed of an iron salt for improving the biological treatment performance used in the biological treatment of an aqueous system containing a biodegradable or slowly degradable organic component and having a CODof 500 mg / L or more, a method for adding the bioactivator, and a biological treatment method. Specifically, the addition amount of the iron salt is in the range of 0.25 to 5.0 mg-Fe 2+ / L, and glycol ethers, nonionic surfactants, polymers, and biopolymeric compounds are described as the biodegradable organic components to be treated.

[0007] Japanese Patent Application Laid-Open No. 2009-119406 (Patent Document 3) describes a wastewater treatment method and an apparatus thereof, which are characterized in that wastewater containing a refractory organic substance is biologically treated by a fluidized bed type biological reaction tank to which a carrier fixed with microorganisms is added, and the biologically treated water is subjected to coagulation separation treatment to coagulate and separate and remove the refractory organic substance from the wastewater. Specifically, regarding the wastewater treatment of wastewater containing a refractory organic substance, the BOD / COD Mn ratio of the wastewater is relatively low, about 0.3, the COD Mn volume loading conditions during operation, and the type of the fluidized carrier are described, and the refractory organic substance in the biologically treated water discharged from the fluidized bed type biological reaction tank is removed by adding a coagulant in the subsequent coagulation separation tank.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, in any of Patent Documents 1 to 3, there is still room for improvement in more efficiently removing refractory organic substances and color components while stably and efficiently performing biological treatment.

[0010] For example, in Patent Document 1, the treatment target is starch, and only the improvement of the starch decomposition rate by activating specific Bacillus bacteria with a biological treatment promoter is examined. Regarding the compatibility between the stabilization and efficiency of biological treatment and the removal treatment of refractory organic substances and color components, no detailed examination has been made.

[0011] In Patent Document 2, the treatment targets are glycol ethers, nonionic surfactants, polymers, and biogenic high molecular compounds. However, in the examples, PEG-600 (average molecular weight: 600) is used. The reduction effect of low-molecular-weight refractory organic substances has been examined, but the effects on refractory organic substances and color components are unclear. Patent Document 3 also treats wastewater containing refractory organic substances with a relatively low BOD / COD ratio of about 0.3 as the treatment target, and the effects on refractory organic substances and color components are unclear. Mn The effects on refractory organic substances and color components are unclear.

[0012] In view of the above problems, the present invention provides a method for treating organic wastewater, a treatment apparatus for organic wastewater, and an agent for removing refractory organic substances and color components in organic wastewater, which can stably and efficiently perform biological treatment and efficiently remove refractory organic substances and color components in organic wastewater.

Means for Solving the Problems

[0013] As a result of intensive studies by the present inventors to solve the above problems, it has been found that it is effective to add a bioactive agent containing iron ions and calcium ions to organic wastewater containing refractory organic substances and color components, and attach microorganisms to a fluid carrier for biological treatment.

[0014] Based on the above findings, the present invention, in one aspect, is a method for treating organic wastewater containing recalcitrant organic matter and chromatic components, which involves adding a biological activator containing iron ions and calcium ions to organic wastewater containing recalcitrant organic matter and chromatic components, introducing a fluidized carrier into the organic wastewater to which the biological activator has been added, and removing recalcitrant organic matter and chromatic components from the organic wastewater by biological treatment caused by attaching microorganisms to the fluidized carrier.

[0015] In one embodiment, the method for treating organic wastewater according to the present invention includes treating organic wastewater containing recalcitrant organic matter with a fractionation molecular weight of 500 or more and chromatic components.

[0016] In another embodiment, the method for treating organic wastewater according to the present invention further includes solid-liquid separation treatment of the biologically treated water obtained by biological treatment.

[0017] In yet another embodiment of the method for treating organic wastewater according to the present invention, a coagulation treatment is performed after biological treatment and before solid-liquid separation treatment.

[0018] In yet another embodiment of the method for treating organic wastewater according to the present invention, the excess sludge obtained from the solid-liquid separation treatment is returned to a treatment tank for biological treatment of the organic wastewater.

[0019] In yet another embodiment of the method for treating organic wastewater according to the present invention, a bound and immobilized carrier is used as a fluid carrier, which has microorganisms attached to or retained on its outer surface, and the carrier is introduced into the treatment tank at a volume of 1 to 50 percent for biological treatment.

[0020] In yet another embodiment of the method for treating organic wastewater according to the present invention, biological treatment is performed such that the rate of increase or decrease in the amount of sludge adhering to the fluidized carrier is within 15% by mass.

[0021] In another aspect, the present invention is an organic wastewater treatment apparatus comprising: an adjustment means for introducing and storing organic wastewater containing recalcitrant organic matter and chromatic components; a biological agent adding means for adding a biological agent containing iron ions and calcium ions to the adjustment means to obtain a biological agent treated solution; a biological treatment means for introducing the biological agent treated solution, bringing a fluid carrier into contact with the biological agent treated solution, and biologically treating the fluid carrier to attach microorganisms, thereby removing recalcitrant organic matter and chromatic components to obtain biologically treated water; a coagulation treatment means for coagulating the biologically treated water to obtain coagulated treated water; and a solid-liquid separation means for solid-liquid separation of the coagulated treated water to obtain treated water.

[0022] In one embodiment of the treatment apparatus for organic wastewater according to the present invention, a fluidized carrier is housed within a conditioning means.

[0023] In another embodiment of the organic wastewater treatment apparatus according to the present invention, a biological activator adding means further adds a biological activator to the biological treatment means.

[0024] In yet another embodiment, the treatment apparatus for organic wastewater according to the present invention uses a bound and immobilized carrier as a fluid carrier that has microorganisms attached to or retained on its outer surface, and the carrier is contained in a treatment tank at a volume of 5 to 50 percent to perform biological treatment.

[0025] In yet another aspect, the present invention relates to an agent for removing recalcitrant organic matter and chromatic components from organic wastewater, which, when a fluidized carrier to which microorganisms are attached is circulated in a treatment tank to biologically treat organic wastewater, improves the activity of the biological treatment while suppressing excessive attachment of microorganisms to the fluidized carrier and maintaining a constant amount, thereby removing recalcitrant organic matter and chromatic components contained in organic wastewater, and contains 1 to 20% by mass of iron ions and calcium ions, and is applied at a concentration of 1 to 300 g / m³ relative to raw water. 3 This is an agent for removing recalcitrant organic matter and color components from organic wastewater that is added to the system. [Effects of the Invention]

[0026] According to the present invention, a method for treating organic wastewater, an apparatus for treating organic wastewater, and an agent for removing recalcitrant organic matter and chromatic components from organic wastewater can be provided, enabling stable and efficient biological treatment and efficient removal of recalcitrant organic matter and chromatic components from organic wastewater. [Brief explanation of the drawing]

[0027] [Figure 1] This is a schematic diagram illustrating a method for treating organic wastewater according to an embodiment of the present invention. [Figure 2] This is a schematic diagram showing a typical organic wastewater treatment device and treatment method according to an embodiment of the present invention. [Figure 3] This is a schematic diagram showing the treatment device and treatment method for organic wastewater relating to the first modified example. [Figure 4] This is a schematic diagram showing a treatment device and treatment method for organic wastewater relating to the second modified example. [Modes for carrying out the invention]

[0028] The meanings of each term used in this disclosure will be explained below, followed by a description of embodiments of the present invention with reference to the drawings. In the following drawings, identical or similar parts are denoted by identical or similar reference numerals. The embodiments shown below are illustrative examples of devices and methods for realizing the technical idea of ​​this invention, and the technical idea of ​​this invention is not limited to the structure, arrangement, etc., of the components described below.

[0029] <Organic wastewater> The organic wastewater that can be used in this embodiment is not particularly limited, and various types of wastewater requiring biological treatment can be used. For example, organic wastewater generated in various industrial wastewater treatments, sewage treatments, human waste treatments, etc., can be used. Wastewater, raw sewage, raw human waste, and dewatered separated liquid after dewatering of wastewater sludge generated in various factories such as soft drink manufacturers, food processing plants, food manufacturing plants, fertilizer manufacturers, machine shops, automobile factories, slaughterhouses, meat processing facilities, and meat processing plants can also be used as organic wastewater according to this embodiment. Furthermore, wastewater generated in various facilities such as shopping centers, restaurants, supermarkets, hotels, and hospitals may also be used as organic wastewater according to this embodiment. Such organic wastewater contains dissolved organic matter and suspended solids (SS), and may further contain inorganic matter.

[0030] <Soluble organic matter> Dissolved organic matter refers to the general term for organic matter in the filtrate filtered through filter paper with a pore size of 1 μm. Specifically, dissolved organic matter is dissolved COD. Cr , soluble COD Mn This refers to substances that are dissolved in a liquid, other than organic matter derived from suspended solids (SS), including soluble BOD, soluble TOC, soluble reducing sugars, and soluble starch.

[0031] <Suspended Solids: SS> SS (Suspended Solids) refers to solid suspended matter floating in wastewater, specifically the substances that remain on filter paper after filtration with a pore size of 1 μm. SS includes both inorganic and organic substances. Inorganic SS includes components derived from soil and clay. Organic SS includes components derived from animal, plant, and microbial cells, as well as components derived from factories. The SS contained in the organic wastewater of this embodiment is not particularly limited, but includes components generated in the manufacturing process of a soft drink factory, activated sludge, sludge detached from fluidized carriers, and SS derived from sludge flocs generated in the coagulation process.

[0032] <Persistent organic matter> Refractory organic substances refer to organic substances that are difficult to decompose or require a long time to decompose through reactions including biological catabolism and assimilation, and typically refer to organic substances with a molecular weight of several hundred or more. Specifically, they are classified as high-molecular organic compounds. For example, oligosaccharides such as dextrin (generally in the fractionation range of a molecular weight of about 300 to 3000), polysaccharides such as starch (fractionation molecular weight above oligosaccharides), cellulose such as glucan and β-glucan, hemicellulose, mucopolysaccharide, protein, amino acid, humin and its complex (molecular weight 10 2 ~10 7 ), compounds or complexes containing any one or more of the above substances such as melanoidin (molecular weight 1000 - 2000) and its complex can be cited as refractory organic substances. Humin and its complex, melanoidin and its complex are also chromaticity components. Refractory organic substances are also called refractory organic substances (components), refractory COD, retarded organic substances (components), retarded BOD, etc.

[0033] <Chromaticity and chromaticity components> In this embodiment, "chromaticity" is an index indicating the degree of water coloring, which is caused by colloidal substances and soluble substances in water. "Chromaticity components" refer to the components presenting this chromaticity. Examples of chromaticity components include metal ions such as iron and manganese, and organic substances such as humin and its complex, melanoidin and its complex. Melanoidin is a component generated by the reaction of sugar and amino acid (Maillard reaction), and typically presents a brown color of "roasted".

[0034] <Fractionation molecular weight> Suitable organic wastewater for biological treatment according to this embodiment is organic wastewater containing recalcitrant organic matter and chromatic components with a fractional molecular weight of 500 or more, in one embodiment 500 to 20,000, and even more so 20,000 or more. There is no particular upper limit to the fractional molecular weight, but it is typically 10,000,000 or less, even more so 1,000,000 or less, and even more so 500,000 or less. Fractional molecular weight refers to the molecular weight fractionated by molar mass when measured using an LC-OCD (Liquid Chromatography-Organic Carbon Detector) analyzer (a liquid chromatograph organic carbon analyzer equipped with a size exclusion column).

[0035] Specifically, in the analysis, the recalcitrant organic matter and organic carbon constituting the chromatic components of organic wastewater are evaluated by dividing them into the following fractions. • Biopolymers (BP): Fractions with a molecular weight of approximately 20,000 or more. • Humic Substance (HS): A fraction with a molecular weight of approximately 500 to 20,000. Building Blocks (BB): Fractions with a molecular weight of approximately 300-500. • LMW Acids (Low Molecular Weight Organic Acids; LA): A fraction of organic acids with a molecular weight of approximately 350 or less. LMW Neutrals (Low Molecular Weight Neutral Substances; LN): A fraction of organic substances other than organic acids with a molecular weight of approximately 350 or less.

[0036] In this embodiment, humic substances, particularly fractions with a molecular weight cutoff of approximately 500 to 20,000, and biopolymers, particularly fractions with a molecular weight of approximately 20,000 or more, can be removed more effectively.

[0037] COD in such organic wastewater CrThe ranges are 10-5,000 mg / L, 100-4,000 mg / L, and even further, 300-3,000 mg / L. The ranges are 10-5,000 mg / L, 50-4,000 mg / L, and even further, 100-3,000 mg / L. The ranges are 10-2,000 degrees, 50-1,500 degrees, and even further, 100-1,000 degrees.

[0038] <Biological Activators> The bioactive agent according to this embodiment contains iron ions and calcium ions and is typically a liquid agent. Iron ions are Fe 2+ or Fe 3+ It refers to calcium ions, and Ca 2+ This refers to the following: By further incorporating calcium ions as a coenzyme for biological treatment in addition to iron ions as a biological activator, it is possible to suppress excessive sludge (biofilm) adhesion to the fluidized carrier during biological treatment while still allowing a certain amount to adhere firmly. As a result, the decomposition activity and physiological activity of organisms involved in the decomposition of recalcitrant organic matter and chromatic components can be improved.

[0039] The compounds containing iron ions are not particularly limited as long as they are water-soluble iron compounds, but examples of preferred examples include polyferric chloride, polyferric sulfate, ferric chloride, ferrous chloride, and iron sulfate. The compounds containing calcium ions are not particularly limited as long as they are water-soluble calcium compounds, but examples of preferred examples include water-soluble calcium compounds such as calcium chloride, calcium hydroxide, calcium oxide, and calcium nitrate.

[0040] The calcium compound and iron compound may be a combination of two or more compounds, or a single compound may be used. The calcium compound and iron compound may also be hydrates. Commercially available powder compounds may be used as these compounds, or commercially available liquid compounds such as an aqueous solution of ferric chloride may be used.

[0041] The biological activator is typically in liquid form, and the concentrations of iron ions and calcium ions in the agent are preferably 1 to 20% by mass, more preferably 1 to 10% by mass, and more preferably 2 to 8% by mass, respectively. The concentrations of calcium ions and iron ions in the biological activator may be calculated from the mass of the compound used and the total mass of the liquid agent, or they may be measured by flame atomic absorption spectrometry or ICP emission spectrometry (both methods conforming to JIS K0102:2019).

[0042] The mixing ratio (mass ratio) of iron ions and calcium ions in the biological activator is preferably adjusted to a calcium ion:iron ion ratio of 1:10 to 10:1, more preferably to 1:5 to 5:1, and even more preferably to 1:3 to 3:1. By optimizing the mixing ratio of iron ions and calcium ions, the decomposition of recalcitrant organic matter in organic wastewater is promoted, and the removal rate of color components is also significantly improved. Furthermore, there are effects such as improved sludge settling due to the coagulation reaction and reduction of treated water SS and treated water turbidity.

[0043] While there are no particular limitations on components other than iron ions and calcium ions, components that enhance microbial growth and biological processing activity may be added. Such components may include nitrogen sources, phosphorus sources, metal sources, recalcitrant organic matter, compounds that contribute to chromatic decomposition, and microorganisms. The components other than iron ions and calcium ions are preferably 50% by mass or less of the total drug, more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0044] When manufacturing biological activators, there are no restrictions on the mixing method or order when mixing calcium compounds and iron compounds. For example, if using powdered compounds of calcium chloride and ferrous chloride as raw materials, they can be mixed in the usual way, such as adding calcium chloride to pure water and mixing with a mixer, then adding ferrous chloride and mixing with a mixer. Alternatively, if using a liquid product such as a 37% aqueous solution of ferric chloride as a raw material, the liquid product can be diluted to an appropriate concentration with pure water, and calcium compounds can be added as needed. There are no restrictions on the temperature when dissolving calcium compounds and iron compounds; they can be dissolved at room temperature, or they can be dissolved while heating as needed by installing an immersion heater or jacket heater in the dissolution tank. The amount of biological activator obtained in this way is calculated based on the volume of raw water (1 m³). 3 A value of 1g to 300g is preferred for / d, 5g to 200g is more preferred, and 10g to 100g is most preferred.

[0045] <Fluid carrier> In this embodiment, aerobic treatment using a fluidized carrier is preferred. By performing aerobic treatment using a fluidized carrier, recalcitrant organic matter and chromatic components in organic wastewater can be reduced more efficiently. As the fluidized carrier, it is possible to use an inclusion-immobilized carrier in which microorganisms are incorporated into the fine lattice structure of the gel and immobilized by an inclusion-immobilization method, but it is preferable to use a bound-immobilized carrier in which microorganisms are immobilized by a binding-immobilization method in which microorganisms are attached to or held on the outer surface of the carrier.

[0046] There are no particular restrictions on the material of the carrier; general materials such as synthetic polymers like polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyacrylamide, and photocurable resins, gel carriers using polymers like carrageenan and sodium alginate, and carriers made of polyethylene, polyurethane, and polypropylene can be used. The carrier can be spherical, square, cylindrical, or porous, and the effective diameter of the carrier before microorganisms adhere to the outer surface is preferably about 1 to 20 mm. The specific surface area of ​​the carrier is 200 to 30,000 m². 2 / m3 , more preferably 200~20,000m 2 / m 3 More preferably 200 to 10,000 m 2 / m 3 Preferably, the specific gravity is 1.01 to 1.1, and more preferably 1.01 to 1.05.

[0047] To efficiently treat organic wastewater containing recalcitrant organic matter and chromatic components, the amount of carrier to be packed is preferably 1 to 50% by volume, more preferably 5 to 40% by volume, and even more preferably 10 to 35% by volume. Furthermore, by placing a carrier having fine pores on its outer surface, or a carrier having fine irregularities on its outer surface, into the treatment tank and adding a biological activator to allow it to acclimate, the attachment and fixation of microorganisms to the outer surface of the carrier can be made stronger.

[0048] On the other hand, the aerobic biological treatment reaction of the attached sludge adhering to the fluidized carrier proceeds only at a surface thickness of a few micrometers on the sludge attached to the fluidized carrier. Therefore, simply increasing the amount of attached sludge does not improve treatment performance. Conversely, if the amount of attached sludge increases too much, the flow efficiency in the treatment tank decreases due to the increased weight of the fluidized carrier, and the power required to move the fluidized carrier increases, which may prevent a significant improvement in treatment efficiency.

[0049] According to this embodiment, by utilizing a bound and immobilized carrier and adding the above-mentioned biological activator that improves the activity of biological treatment, it is possible to improve treatment efficiency without changing the flow efficiency of the fluidized carrier or the power required to fluidize it, while maintaining the treatment performance of organic wastewater.

[0050] (Methods for treating organic wastewater) As shown in Figure 1, the method for treating organic wastewater according to an embodiment of the present invention includes the steps of: adding a biological activator containing iron ions and calcium ions to organic wastewater containing recalcitrant organic matter and chromatic components; introducing a fluidized carrier into the organic wastewater to which the biological activator has been added; and removing recalcitrant organic matter and chromatic components from the organic wastewater by biological treatment through the attachment of microorganisms to the fluidized carrier.

[0051] <Biological treatment> The biological activator according to this embodiment can be added to and used at biological treatment sites. Examples of biological treatment methods include nitrification and denitrification methods such as the circulating nitrification and denitrification method, the step nitrification and denitrification method, and the direct dewatering (pre-dewatering) type denitrification treatment method, as well as aerobic activated sludge methods such as the standard activated sludge method, oxidation ditch method, deep tank aeration method, and step aeration method, and aerobic biofilm methods using fluidized carriers, fixed-bed immersion filter methods, fluidized-bed immersion filter methods, and rotating disc methods. It can also be used appropriately at sites where treatment of organic wastewater is required, such as anaerobic treatment tanks, methane fermentation tanks, biological deodorization tanks, and compost fermentation tanks.

[0052] The biological activator may be supplied directly into the treatment tank of the biological treatment means 2 containing the fluidized carrier, or it may be supplied to the piping for introducing organic wastewater to the biological treatment means 2 upstream. When the biological activator is added to organic wastewater, the excessive attachment of biofilm to the fluidized carrier is suppressed by the effect of the biological activator, and a certain amount of biofilm is firmly maintained on the fluidized carrier. As a result, the biological treatment activity is improved, and the biological treatment proceeds stably while promoting the reduction of recalcitrant organic matter and chromatic components.

[0053] More preferably, as shown in Figure 2, the method for treating organic wastewater according to an embodiment of the present invention includes: a storage step of introducing and storing organic wastewater containing recalcitrant organic matter and chromatic components into an adjustment means 1; a pretreatment step of adding a biological activator containing iron ions and calcium ions to the adjustment means 1 to obtain a biological activator treatment solution; a biological treatment step of introducing the biological activator treatment solution into a biological treatment means 2, bringing the biological activator treatment solution into contact with a fluid carrier contained inside a treatment tank to cause microorganisms to adhere to the fluid carrier and perform biological treatment to remove recalcitrant organic matter and chromatic components and obtain biologically treated water; a coagulation treatment step of coagulating the biologically treated water obtained from the biological treatment to obtain coagulated water; a solid-liquid separation treatment step of solid-liquid separation of the coagulated water to obtain treated water and excess sludge; and a return step of returning the excess sludge obtained from the solid-liquid separation treatment step to the adjustment means 1 and / or biological treatment means 2.

[0054] Organic wastewater is introduced into adjustment means 1, which is equipped with a treatment tank such as a storage tank. A biological activator containing iron ions and calcium ions is then added to adjustment means 1 by a biological activator addition means 3. The biological activator treatment liquid, which is a mixture of organic wastewater and the biological activator, is introduced into biological treatment means 2, where biological treatment is carried out. A fluidized carrier is introduced into the treatment tank of biological treatment means 2, where biological treatment is carried out under aerobic conditions while microorganisms adhere to the fluidized carrier. Due to the effect of the biological activator, the amount of excessive sludge adhesion to the fluidized carrier is suppressed, and a certain amount of biofilm is firmly maintained on the surface of the fluidized carrier, so the biological treatment activity is improved, the reduction of recalcitrant organic matter and chromatic components is promoted, and the treatment proceeds.

[0055] In the adjustment and pretreatment processes, it is preferable to introduce a fluidized carrier into the treatment tank to increase the residence time of microorganisms such as activated sludge in biological treatment under aerobic conditions, maintain their abundance, and improve contact efficiency with the target components. This allows for optimization of the reaction tank volume and further stabilization of the treated water capacity. In this embodiment, the effect of the biological activator makes it possible to maintain a constant amount of sludge adhesion, preventing excessive sludge adhesion and maintaining a constant amount of sludge in the treatment tank, thus stabilizing treatment performance. Furthermore, treatment can be carried out without significantly changing the fluidization efficiency of the fluidized carrier or the power required to fluidize it.

[0056] By adding the biological activator to both the adjusting means 1 and the biological treatment means 2, the recalcitrant organic matter and chromatic components contained in the organic wastewater are made more readily absorbed by the microorganisms that treat the recalcitrant organic matter and chromatic components. Preferably, the amount of biological activator added is adjusted so that the total amount added to adjusting means 1 and biological treatment means 2 or the preceding step falls within a predetermined range.

[0057] In order to achieve both the stabilization of biological treatment and the removal of recalcitrant organic matter and chromatic components, for example, when a biological activator is added to both the adjusting means 1 and the biological treatment means 2, it is preferable that the ratio of the biological activator added to the adjusting means 1 and the biological treatment means 2 be 10:1 to 1:10.

[0058] In the biological treatment means 2, the pH in the treatment tank is preferably in the range of 6.0 to 8.5, and more preferably in the range of 7.0 to 8.0. In the biological treatment means 2, it is preferable to supply oxygen-containing gas such as air into the treatment tank via the aeration means 21. In this case, the dissolved oxygen concentration (DO) in the treatment tank is preferably 2 to 8 mg / L, and more preferably 2 to 5 mg / L. The water temperature is preferably 15 to 35°C, and more preferably 20 to 30°C. COD of the treatment tank Cr Volumetric load is 0.1 to 20 kg / m³. 3 A range of / d is preferred, and 0.3 to 10 kg / m 3 A range of / d is more preferable, 0.5 to 5 kg / m 3 The range of / d is most preferable. The BOD volumetric load is 0.05 to 10 kg / m³. 3 A range of / d is preferred, and 0.15 to 5 kg / m 3 A range of / d is more preferable, between 0.25 and 2.5 kg / m 3 The range / d is the most preferable.

[0059] In order to stably and efficiently remove recalcitrant organic matter and chromatic components from organic wastewater in biological treatment, it is preferable to adjust the amount of sludge adhering to the fluidized carrier to a certain range. After various studies, it was found that when using a fluidized carrier, the amount of sludge adhering to the carrier (sludge adhesion amount) is preferably 5 to 60 mg-SS / piece, more preferably 10 to 50 mg-SS / piece, and even more preferably 15 to 22 mg-SS / piece. Alternatively, it is preferable that the amount of sludge adhering to the carrier is 5 to 40 mg-VSS / piece, more preferably 10 to 20 mg-VSS / piece, and even more preferably 15 to 18 mg-VSS / piece.

[0060] To analyze the amount of sludge adhering to the fluidized carrier, after collecting the treated water from the treatment tank, the adhering sludge equivalent to 3 to 5 fluidized carriers is detached using glass filter paper with a pore size of 1 mm and suspended in pure water. By measuring the MLSS (Mixed Liquor Suspended Solids) of the suspension, the MLSS weight per carrier (mg-SS / carrier) is calculated. The same procedure is followed for MLVSS (Mixed Liquor Volatile Suspended Solids), which is the amount of sludge adhering to the MLVSS standard, and the MLVSS weight per carrier (mg-VSS / carrier) is measured in the same manner.

[0061] In biological treatment, if the amount of sludge adhering to the fluidized carrier increases or decreases over time, it may not be possible to stably and efficiently remove recalcitrant organic matter and chromatic components from organic wastewater. Therefore, in the organic wastewater treatment method according to the embodiment of the present invention, while adding a biological activator, the biological treatment is carried out while keeping the rate of increase or decrease in the amount of sludge adhering to the carrier within 15%, more preferably within 13%, even more preferably within 10%, and even more preferably within 8%. The lower limit of the rate of increase or decrease in the amount of sludge adhering is not particularly limited, but is typically 1% or more, and more preferably 3% or more.

[0062] The percentage increase or decrease in sludge adhesion is determined by taking treated water containing the fluidized carrier at arbitrary time intervals, for example, approximately every two weeks (the number of times is not limited to three), once the biological treatment has stabilized and reached a steady state. The amount of sludge adhering to the fluidized carrier is then measured. The squared error (variance) is calculated from each measured value and its mean value. The standard deviation is then calculated from the square root of the variance, and the percentage of the standard deviation relative to the mean value is used as the value. This percentage increase or decrease indicates the stability of sludge adhesion to the carrier; a small value indicates that the amount of sludge adhesion is constant.

[0063] In the biological treatment according to this embodiment, it is preferable to biologically treat the biologically activated water to which a biological activator has been added so that the MLSS equivalent value of the fluidized carrier per unit volume of the treatment tank is 100 to 7,000 mg-SS / L, more preferably 500 to 5,000 mg-SS / L, and even more preferably 1,000 to 3,000 mg-SS / L. Furthermore, it is preferable to biologically treat the biologically activated water to which a biological activator has been added so that the MLVSS equivalent value of the fluidized carrier per unit volume of the treatment tank for biological treatment is 100 to 6,000 mg-VSS / L, more preferably 300 to 5,000 mg-VSS / L, even more preferably 1,000 to 2,000 mg-VSS / L, and in yet another embodiment, it can be 1,000 to 1,700 mg-VSS / L.

[0064] The MLSS equivalent value is calculated by multiplying the MLSS weight (sludge adhesion amount) per carrier by the total number of fluidized carriers introduced into the aeration tank, and then dividing that value by the volume of the aeration tank. The MLVSS equivalent value is calculated in the same way, using the MLVSS weight (sludge adhesion amount) per carrier. Since MLVSS is the value obtained by subtracting the inorganic content from MLSS, it serves as an indicator of the amount of biomass in activated sludge or attached sludge. In the biological treatment process, nutrients such as nitrogen sources and phosphorus sources are necessary for aerobic organic matter treatment, so they may be added as appropriate so that BOD:total nitrogen:total phosphorus = approximately 100:5:1.

[0065] The biologically treated water, after undergoing biological treatment, flows into the coagulation treatment means 4, where a coagulant is added to and mixed with the biologically treated water. SS components, SS-derived components, dissolved organic components, and nutrients in the biologically treated water are converted into sludge flocs through a coagulation reaction. The coagulated treated water and sludge flocs obtained from the coagulation reaction are sent to the solid-liquid separation means 5, where the solids and treated water are separated. The treated water is discharged outside the system. The solids and some of the treated water are transported out of the system as excess sludge by the sludge return means 6, but a certain amount can also be returned to the storage process, pre-treatment process, or an earlier stage therefor. By returning the sludge flocs and a portion of the treated water to the storage process, pre-treatment process, or an earlier stage therefor, the biological treatment reaction in the storage process or pre-treatment process can be promoted, and effects such as maintaining the sludge concentration in the biological treatment process and reducing the amount of coagulant used in the coagulation treatment process can be obtained.

[0066] (Treatment for organic wastewater) As shown in Figure 2, the organic wastewater treatment apparatus according to an embodiment of the present invention comprises: an adjustment means 1 for introducing and storing organic wastewater containing recalcitrant organic matter and chromatic components; a bioactivator adding means 3 for adding a bioactivator containing iron ions and calcium ions to the adjustment means 1 to obtain a bioactivator treatment solution; a biotreatment means 2 for introducing the bioactivator treatment solution and bringing a fluid carrier into contact with the bioactivator treatment solution to allow microorganisms to adhere to the fluid carrier and perform biological treatment to remove recalcitrant organic matter and chromatic components and obtain biologically treated water; a coagulation treatment means 4 for coagulating the biologically treated water to obtain coagulated treated water; and a solid-liquid separation means 5 for solid-liquid separation of the coagulated treated water to obtain treated water.

[0067] Adjustment means 1 is a means for temporarily storing organic wastewater, excess sludge (treated water and sludge flocs) returned from sludge return means 6, and biological activators added from biological activator addition means 3, and adjusting the flow rate in the subsequent stage. By creating aerobic conditions in the treatment tank of adjustment means 1, it is possible to partially advance the biological treatment. Specifically, adjustment means 1 consists of an adjustment tank (treatment tank) into which organic wastewater containing recalcitrant organic matter and chromaticity, the treated water and sludge flocs, and biological activators added from the biological activator addition step flow in. The number of adjustment tanks is not particularly limited, but their number and volume are determined by the organic matter load conditions of the inflowing wastewater. Furthermore, it is possible to install a coarse or fine screen with a pore size of several mm, an automatic dust remover, etc., in front of the adjustment tank to prevent the inflow of impurities such as sludge and large suspended solids. In addition, it is possible to install an air aeration device in the adjustment tank, which allows the biological treatment reaction to partially advance and reduces the organic matter load before the biological treatment step.

[0068] The biological treatment means 2 is a means of biologically treating raw water that has undergone storage and pretreatment in the adjustment means 1 under aerobic conditions using aerobic organisms to reduce, decompose, and remove recalcitrant organic matter and chromatic components, other easily decomposable organic matter, nutrients, etc. in the raw water. The biological treatment means 2 consists of a treatment tank, aeration means, etc. It is also possible to install a membrane separation unit in the treatment tank of the biological treatment means 2 and operate it as a membrane bioreactor (MBR) treatment system.

[0069] The biological activator addition means 3 is a means for adding a biological activator to organic wastewater. The details of the biological activator addition means 3 are not particularly limited, but since the drug is typically in liquid form, it consists of, for example, a chemical storage tank, a chemical dissolving tank, a chemical injection pump, and piping attached thereto.

[0070] The coagulation treatment means 4 is a means of adding and mixing a coagulant to the biologically treated water that has undergone the biological treatment process in the biological treatment means 2, thereby generating sludge flocs that capture organic matter and suspended solids (SS) components in the water to be treated. As shown in Figure 3, the coagulation treatment means 4 can also be arranged by combining multiple means such as mixing means 4a, which performs mixing treatment of a coagulant such as an inorganic coagulant, and coagulation means 4b, which performs coagulation treatment by adding a polymer coagulant or the like.

[0071] A mechanical agitator can be installed in the treatment tank of the coagulation means 4b, and its shape, number, and rotation speed are appropriately determined so that the sludge flocs can be easily separated into solid and liquid in the subsequent solid-liquid separation process. Furthermore, it is preferable that the residence time of the treated water and sludge flocs in each tank be set to conditions that allow the subsequent processes to be carried out efficiently.

[0072] The type and amount of flocculant added are not particularly limited, but either inorganic or organic flocculants are acceptable, and one or more types can be added in combination. While the type of inorganic flocculant is not particularly limited, aluminum sulfate, polyaluminum chloride (PAC), aluminum chloride, polyferric sulfate (polyiron), ferric sulfate, ferric chloride, or mixtures thereof can be used. Organic flocculants are generally called polymer flocculants or organic coagulants. There are no particular restrictions on the type of organic flocculant, but those with various physical properties such as cationic, anionic, amphoteric, and nonionic types can be used.

[0073] To adjust the pH in the treatment tank, a pH adjuster can be added before the coagulant. The type of acid is not particularly limited, but examples include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and boric acid. Examples of alkaline agents include sodium hydroxide, magnesium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, calcium carbonate, potassium carbonate, magnesium carbonate, sodium bicarbonate, ammonium hydroxide, ammonium carbonate, or hydrates thereof. The means of adding the coagulant and pH adjuster are not particularly limited, but if the chemical is in liquid form, examples include chemical storage tanks, chemical dissolving tanks, chemical injection pumps, and associated piping. If the chemical is in powder form, examples include chemical feeders and chemical storage tanks, and chemical input devices.

[0074] The solid-liquid separation means 5 is a process of separating the coagulated water treated by the coagulation treatment means 4 into sludge flocs and treated water. The separated sludge flocs are discharged outside the system and dewatered in a sludge dewatering treatment facility. Alternatively, a portion of the separated sludge flocs and treated water are returned via the sludge return means 6 to the adjustment means 1 or its preceding piping and equipment, or to the biological treatment means 2 or its preceding piping and equipment. The treated water is either discharged or subjected to advanced treatment such as coagulation and sedimentation. The specific device configuration of the solid-liquid separation means 5 is not particularly limited, but examples include gravity sedimentation, coagulation and sedimentation, pressurized flotation, and membrane separation. From an economic standpoint, gravity sedimentation is preferred.

[0075] The sludge return means 6 is a means for returning the sludge flocs separated by the solid-liquid separation process to the outside of the system or to the adjustment means 1 or the biological treatment means 2, and consists of a sludge transfer or sludge return pump and its associated piping, etc. The amount of sludge flocs returned is not particularly limited, but is preferably in the range of 0.5 to 40 volume percent, and more preferably in the range of 1 to 30 volume percent, relative to the raw water inflow. Any remaining sludge flocs are discharged outside the system.

[0076] According to the method for treating organic wastewater according to an embodiment of the present invention, by adding a bioactive agent containing iron ions and calcium ions to the organic wastewater, excessive adhesion of biofilm to the fluidized carrier is suppressed, and a certain amount of biofilm is firmly maintained on the fluidized carrier. As a result, the biological treatment activity is improved, and stable biological treatment can be performed while promoting the reduction of recalcitrant organic matter and chromatic components.

[0077] (First variation) As shown in Figure 3, a treatment apparatus can also be suitably used in which a solid-liquid separation means 5a is provided downstream of the biological treatment means 2, a mixing means 4a and a coagulation means 4b are provided downstream of the solid-liquid separation means 5a, and another solid-liquid separation means 5b is provided downstream of the coagulation means 4b. That is, the first modified example shown in Figure 3 differs from the treatment apparatus in Figure 2 in that it further includes a step of solid-liquid separation treatment of the biologically treated water obtained from the biological treatment, and then coagulation treatment is performed via the mixing means 4a and the coagulation means 4b. The rest of the configuration can be the same as that of the treatment apparatus in Figure 2.

[0078] In the first modified example, a biological activator is added to both the adjusting means 1 and the biological treatment means 2, and the fluidized carrier is placed in each to perform biological treatment. In this case, the organic matter loading conditions in adjusting means 1 are set to be higher than those of a typical activated sludge method, and the organic matter loading conditions in biological treatment means 2 are set to be lower than those of adjusting means 1, and both perform biological treatment under aerobic conditions. Specifically, the organic matter loading is set to a BOD volumetric load of 1-5 kg / m³ in adjusting means 1. 3 The reaction vessel volume and flow rate are adjusted so that the ratio is / d. Furthermore, from the viewpoint of treatment stability, it is also preferable to adjust the load conditions in adjustment means 1 and biological treatment means 2 so that the overall MLSS of adjustment means 1 and biological treatment means 2 is in the range of 500 to 8,000 mg / L, and more preferably in the range of 1,000 to 6,000 mg / L. According to the first modification, it is possible to respond to fluctuations in the organic matter load of the raw water.

[0079] (Second variation) As shown in Figure 4, the second modified organic wastewater treatment apparatus according to the present invention includes a biological agent storage tank 31 for storing the biological agent as a biological agent addition means 3. Furthermore, this apparatus differs from the apparatus in Figure 3 in that it includes an inorganic flocculant addition means 7 equipped with an inorganic flocculant storage tank 71 for dissolving and storing an inorganic flocculant to be added to the mixing means 4a, and a polymer flocculant addition means 8 equipped with a polymer flocculant dissolving tank 81 for dissolving and storing a polymer flocculant to be added to the flocculation means 4b. According to the second modified apparatus, by storing the agent in each storage tank, the biological agent or flocculant adjusted to the appropriate concentration can be supplied without excess or deficiency to each treatment tank of the adjusting means 1, mixing means 4a, and flocculation means 4b, so that each treatment can be performed stably.

[0080] According to the organic wastewater treatment method and treatment apparatus according to the embodiment of the present invention, the treatment performance of dissolved organic matter and chromatic components, including recalcitrant organic matter with a fractional molecular weight of 500 or more, can be improved by the effect of enhancing biological treatment activity through a biological treatment process using a biological activator. Furthermore, the amount of excessive sludge adhesion to the fluidized carrier can be suppressed and stabilized. In addition, the efficiency of the coagulation and sedimentation treatment can be improved, i.e., the amount of coagulant used can be reduced, and the site area and treatment equipment can be made more compact. Since the treated water obtained by this treatment contains relatively few components such as nutrients, the advanced treatment that is performed afterward as needed can be simplified and shortened. [Examples]

[0081] Examples of the present invention are shown below, but these examples are provided to better understand the present invention and its advantages, and are not intended to limit the invention.

[0082] <Evaluation test of improved treatment performance for dissolved organic matter and chromatic components in continuous water flow tests> Table 1 shows the properties of raw water a. A commercially available diluted barley tea solution was used as raw water a (organic wastewater). The properties of raw water a (average values) were pH: 7.1, SS: 1 mg / L or less, COD Cr : 795 mg / L, COD MnThe concentrations were 487 mg / L, BOD: 403 mg / L, TOC: 287 mg / L, total nitrogen (TN): 23.7 mg / L, total phosphorus (TP): 5.7 mg / L, reducing sugars: 522 mg / L, starch: 220 mg / L, and chromaticity: 245 degrees. Aqueous solutions of ammonium chloride and potassium hydrogen phosphate were added to the raw water a so that the BOD:N:P ratio was 100:5:1. Furthermore, an aqueous solution of sodium bicarbonate was added as needed to prepare for the decrease in pH due to the nitrification reaction in the aeration tank (biological treatment method). The test conditions are shown in Table 2.

[0083] [Table 1]

[0084] [Table 2]

[0085] The test apparatus consisted of a raw water tank (conditioning means), an aeration tank (first biological treatment means), and a treated water tank (second biological treatment tank), with raw water and treated water continuously flowing through them in the order described above. The volume of the aeration tank was 2 L, and a fluidized carrier was added to the aeration tank. The carrier filling rate of the fluidized carrier was 35% by volume. A polyethylene carrier was used for the fluidized carrier. The aeration tank was kept warm and constantly aerated with air through diffusers to maintain the water temperature and aerobic conditions in the aeration tank. The water temperature in the aeration tank was 19-23°C, the pH was 6-8, and the DO was 8-9 mg / L. The test groups consisted of an acclimatization period (acclimatization 1 and 2) and a test period (test 1 and 2), each consisting of two series: a comparative example and an example. During the acclimatization period, COD was measured. Cr The BOD volumetric load was gradually increased to increase the amount of sludge adhering to the fluidized carrier. In Test 1, the organic matter load conditions were further increased from acclimatization 1, and the amount of bioactivator added was 100 mg / L. In Test 2, the organic matter volumetric load was kept the same, and the amount of bioactivator added was 30 mg / L. The treatment performance of dissolved organic matter and chromatic components was examined under these conditions.

[0086] Water quality parameters: HOME, SS, COD Cr COD MnThe measurement methods for BOD, TOC, TN, NH4-N, NO3-N, TP, PO4-P, chromaticity, MLSS, and MLVSS followed the Sewage Test Methods (published by the Japan Sewage Works Association). The measurement method for reducing sugars followed the phenol-sulfuric acid method ("Quantitative Method of Reducing Sugars," Gakkai Shuppan Center, authored by Sakuzo Fukui), and the measurement method for starch followed the total starch content measurement method (K-TSHK) of the total starch content measurement kit (Megazyme, Nippon Biocon Co., Ltd.). For the analysis of treated water, after sampling, glass filter paper with a pore size of 1 mm was used to determine the amount of sludge attached. The attached sludge equivalent to 3 to 5 fluidized carriers was detached, suspended in pure water, and the MLSS was measured. The MLSS weight per carrier (mg-SS / carrier) was calculated. The same method was used for MLVSS (mg-VSS / carrier). The MLSS equivalent value was calculated by multiplying the MLSS weight (sludge adhesion amount) per carrier by the total number of fluid carriers introduced into the aeration tank and dividing the result by the volume of the aeration tank. The MLVSS equivalent value was calculated in the same way, using the MLVSS weight (sludge adhesion amount) per carrier as described above. Furthermore, the average value of each sludge adhesion amount was calculated, the squared error (variance) was calculated from the average value and the measured value, and the standard deviation was calculated from the square root of the variance. In this example, the percentage of the standard deviation relative to the average value was calculated and used as the percentage of increase or decrease in sludge adhesion amount.

[0087] The biological activator was added to the aeration tank once a day at a concentration of 100 mg / L in Test 1 and 30 mg / L in Test 2 relative to the raw water inflow. The biological activator contained CaCl2·2H2O as the calcium component, FeCl3 (37% solution) as the iron component, and water, with each compound having a concentration of 10% by mass. Table 3 shows the treated water quality in the continuous water flow test, and Table 4 shows the amount of sludge adhering to the fluidized carrier.

[0088] [Table 3]

[0089] [Table 4]

[0090] [Table 5]

[0091] (Treated water quality) The average value of the treated water quality in the comparative example in Test 1 was S-COD. Cr : 95 mg / L, S-COD Mn The values ​​were: 49.1 mg / L, S-TOC: 33.5 mg / L, S-reducing sugar: 30.4 mg / L, S-color: 193 degrees. In contrast, the average value of the treated water quality in the example was S-COD Cr : 65 mg / L, S-COD Mn The concentrations were 32.5 mg / L for soluble organic matter, 21.9 mg / L for S-TOC, 16.1 mg / L for S-reducing sugars, and 130 degrees for S-chromaticity. Under the condition of adding 100 mg / L of bioactive agent, the example showed a reduction in soluble organic matter concentration and chromaticity component.

[0092] The average value of the treated water quality in the comparative example in Test 2 was S-COD. Cr : 138 mg / L, S-COD Mn The values ​​were: 79.5 mg / L, S-TOC: 53.2 mg / L, S-reducing sugar: 53.7 mg / L, S-color: 246 degrees. In contrast, the average value of the treated water quality in the example was S-COD Cr : 89 mg / L, S-COD Mn The concentrations were 48 mg / L for soluble organic matter, 33.3 mg / L for S-TOC, 27.7 mg / L for S-reducing sugars, and 192 degrees for S-chromaticity. Even under the condition of adding 30 mg / L of biological activator, the examples showed a reduction in soluble organic matter concentration and chromaticity components. Furthermore, S-BOD and S-starch in tests 1 and 2 were reduced to below the limit of quantification.

[0093] (Amount of sludge attached) The amount of sludge adhering to the comparative example was 17.1 to 33.0 mg-SS / grain (average 22.6 mg-SS / grain) in Test 1 and 18.3 to 27.0 mg-SS / grain (average 23.2 mg-SS / grain) in Test 2. Furthermore, the percentage increase or decrease in sludge adhering to the comparative example (relative to SS) was 33% in Test 1 and 16% in Test 2. In contrast, the amount of sludge adhering to the example was 18.3 to 22.0 mg-SS / grain (average 20.1 mg-SS / grain) in Test 1 and 15.5 to 17.8 mg-SS / grain (average 16.5 mg-SS / grain) in Test 2. Furthermore, the percentage increase or decrease in sludge adhering to the example (relative to SS) was 7.5% in Test 1 and 5.9% in Test 2.

[0094] According to this test, applying the treatment method according to this embodiment resulted in minimal changes in the amount of sludge adhering to the carrier, and the increase or decrease in the amount of sludge adhering during treatment was small and stable, resulting in a low amount of sludge adhering. Furthermore, when only the fluidized carrier was placed in a container and mechanically agitated, a large amount of sludge detachment occurred in the comparative example, whereas almost no detachment occurred in the example. In other words, according to the present invention, stable treatment can be performed even when the amount of sludge adhering to the carrier is small, and it was found that a larger amount of dissolved organic matter and chromatic components can be reduced with a small amount of sludge. Generally, treatment performance decreases when the amount of sludge adhering is small, but the opposite result was obtained in the present invention. In addition, from the evaluation results of the rate of increase or decrease in the amount of sludge adhering, it can be seen that supplying this biological activator has the effect of continuously and stably adhering and retaining a certain amount of sludge on the carrier. In other words, by adding the biological activator according to the embodiment of the present invention and treating by adhering and fixing a predetermined amount of microorganisms on the surface of the carrier, the adhesion strength of sludge to the fluidized carrier can be strengthened, and the treatment performance of biological treatment can be improved.

[0095] <Agglomeration treatment test after biological treatment> In this study, we conducted tests simulating the treatment of treated water and suspended solids (SS) components after a biological treatment process in a coagulation treatment process. The target water quality value for the treated water after the coagulation treatment test was S-COD. Mn The concentration was set at less than 25 mg / L, and the S-color was set at less than 100 degrees.

[0096] Table 6 shows the raw water properties. The raw water used in the coagulation treatment test was the treated water for one day during the second period of the continuous water flow test described above. The raw water properties of raw water b were pH: 7.4, SS: 145 mg / L, S-COD Mn The concentration was 73.6 mg / L, and the S-color was 260 degrees. The raw water c had a pH of 7.4, SS of 145 mg / L, and S-COD Mn The values ​​were 45.0 mg / L and S-chromaticity: 220 degrees. Similar to the results of the continuous water flow test described above, the example showed a reduction in soluble organic matter and chromaticity components.

[0097] [Table 6]

[0098] The following steps were used to process the data. 1) The temperature of raw water b was adjusted to 20°C, and an appropriate amount was dispensed into a beaker. 2) A polyaluminum chloride solution (PAC volume) was added to a predetermined concentration of 200-500 mg / L, and the pH was adjusted to neutral using an aqueous sodium hydroxide solution or sulfuric acid. 3) An anionic polymer flocculant was added to a concentration of 1.0 mg / L, and the mixture was rapidly stirred (150 rpm, 1 minute). 4) The mixture was switched to slow stirring (50 rpm, 5 minutes) to allow the flocs to grow, and the condition of the flocs was visually checked. 5) After standing for 2 minutes and removing suspended matter from the water surface, the supernatant water was collected. The supernatant water was filtered through a glass fiber filter (pore size 1 μm), and the filtrate was subjected to water quality analysis (S-COD). Mn It was subjected to S-chromaticity testing.

[0099] (Test results) Table 7 shows the water quality of the treated water after the coagulation treatment test. In the comparative example, the treated water quality when PAC was added at 300 mg / L was S-COD Mn The S-COD was 34.7 mg / L and 100 degrees. In the example, the treated water quality when PAC was added at 300 mg / L was S-COD MnThe values ​​were 21.9 mg / L and S-colority: 70 degrees, with only the example achieving the target value. In the comparative example, the target value could not be achieved even with a PAC addition of 500 mg / L. Therefore, it can be seen that the example is able to reduce the treated water quality and reduce the amount of coagulant used in the treatment process, including the biological treatment and coagulation treatment processes. Furthermore, in the comparative example, a subsequent treatment process is required to further improve the treated water quality, but it was confirmed that this is not necessary in the example.

[0100] [Table 7]

[0101] <Regarding the flocculation effect of biological activators> This test was conducted to confirm whether dissolved organic matter and chromatic components were removed by physicochemical coagulation reactions using a biological activator. The test was a 24-hour batch test after the addition of the biological activator, and the water quality of the treated water over time was confirmed.

[0102] Table 8 shows the properties of raw water d. Raw water d was the treated water from the test series of the continuous water flow test described above, and in the comparative example, a sample taken over one day during the operation period of Test 2 was used. Raw water properties: pH: 7, S-COD Cr : 116 mg / L, S-TOC: 46.5 mg / L, S-chromaticity: 260 mg / L.

[0103] [Table 8]

[0104] The following steps were used to process the data. 1) Raw water was collected in a 1L graduated cylinder and thoroughly aerated with air at room temperature. 2) After confirming that the DO was 8.0 or higher, 100 mg / L of a biological activator was added, and aeration was started. The test period was 24 hours. 3) Sample several mL at a time, centrifuge (3,000 rpm, 5 minutes), and filter through a glass fiber filter (pore size 1.0 μm) to obtain S-COD CrWater quality analysis was performed using S-TOC and S-chromaticity. The change in treated water quality up to 24 hours after the start of the test was evaluated.

[0105] (Test results) Table 9 shows the treated water quality after the coagulation treatment test. The treated water quality of the comparative example 24 hours after the start of the test is S-COD Cr The values ​​were 117 mg / L, S-TOC: 44.0 mg / L, and S-chromaticity: 260 degrees, with almost no change before and after the test. The treated water quality of the example 24 hours after the start of the test was S-COD Cr The concentrations were 118 mg / L, S-TOC: 44.2 mg / L, and S-chromaticity: 270 degrees. A slight decrease in concentration was observed between 10 minutes and 6 hours after the start of the test, but no final change was observed. Furthermore, the changes in each concentration during the test were slight and did not show the concentration differences seen in the continuous water flow test results described above.

[0106] From these results, it was inferred that the reduction of dissolved organic matter and chromatic components due to the physicochemical flocculation effect of the biological activator was slight, and that the effect of the biological activator on reducing dissolved organic matter and chromatic components was a biological effect due to the improved activity of the biological treatment reaction.

[0107] [Table 9]

[0108] <Regarding the molecular weight cutoff of recalcitrant organic matter and chromatic components contained in raw water> In this study, in order to obtain detailed information on dissolved organic matter and chromaticity components reduced by the biological activator, molecular weight cutoff measurements were performed on raw water a and treated water during the continuous water flow test described above. The treated water was collected during the period of Test 1 of the continuous water flow test described above.

[0109] The procedure for the test method was as follows: 1) The sample was filtered using a 0.45 μm PTFE membrane filter and diluted with ultrapure water to prepare the sample. 2) The prepared samples were measured using an LC-OCD analyzer (LC-OCD Model 8, DOC-Labor) to determine the molecular weight of the organic compounds.

[0110] (Test results) Table 10 shows the test results. In Table 10, DOC represents dissolved organic carbon content, HOC represents hydrophobic organic carbon content, and CDOC represents colored dissolved organic carbon content. The molecular weight cutoffs of organic matter in raw water a were as follows: BP (20,000 or more): 71 mg / L, HS (approximately 500-20,000): 151 mg / L, BB (approximately 300-500): 33 mg / L, Neutral (components other than organic acids with a molecular weight of approximately 350 or less): 20 mg / L, and Acid (organic acid components with a molecular weight of approximately 350 or less): 8.1 mg / L. In the comparative example, the molecular weight cutoffs of organic matter in the treated water were BP (20,000 or more): 12 mg / L, HS (approximately 500-20,000 Da): 2.6 mg / L, BB (approximately 300-500): 3.3 mg / L, Neutral (components other than organic acids with a molecular weight of approximately 350 or less): 2.9 mg / L, and Acid (organic acid components with a molecular weight of approximately 350 or less): 1.7 mg / L. In the example, the relative abundance of the molecular weight cutoffs of organic matter in the treated water was BP (20,000 or more): 5 mg / L, HS (approximately 500-20,000 Da): 1.8 mg / L, BB (approximately 300-500 Da): 2.5 mg / L, Neutral (components other than organic acids with a molecular weight of approximately 350 or less): 2.3 mg / L, and Acid (organic acid components with a molecular weight of approximately 350 or less): 1.2 mg / L. It was confirmed that low-molecular-weight components such as BB, Neutral, and Acid, along with components with a molecular weight of 500 or more, such as BP and HS, were reduced.

[0111] [Table 10]

[0112] Thus, according to the present invention, the biological activity of microorganisms that process both low-molecular-weight organic matter and organic matter with a fractionation molecular weight of 500 or more can be improved by adding a biological activator. This makes it possible to perform biological treatment stably and efficiently, and to efficiently remove recalcitrant organic matter and chromatic components from organic wastewater. [Explanation of Symbols]

[0113] 1…Adjustment means 2... Biological treatment methods 3. Means of adding bioactive agents 4. Aggregation treatment means 4a…Mixing means 4b…Agglutination means 5, 5a, 5b...Solid-liquid separation means 6. Means of returning sludge 7. Means of adding inorganic flocculants 8. Means of adding polymer flocculants 21... Aeration methods 31…Biologically active agent storage tank 71…Inorganic flocculant storage tank 81… Polymer flocculant dissolution tank

Claims

1. To organic wastewater containing chromatic components and recalcitrant organic matter with a molecular weight cutoff of 500 or more, a biological activator containing iron ions, calcium ions, and water is added. The organic wastewater to which the biological activator has been added is mixed with a fluidized carrier, and microorganisms are attached to the fluidized carrier so that the amount of sludge adhering to the fluidized carrier is 5 to 60 mg-SS / unit, thereby removing the recalcitrant organic matter and the chromatic components from the organic wastewater through biological treatment. A method for treating organic wastewater, characterized by having [a certain characteristic].

2. The method for treating organic wastewater according to claim 1, further comprising solid-liquid separation treatment of the biologically treated water obtained by the biological treatment.

3. The method for treating organic wastewater according to claim 2, characterized in that a coagulation treatment is performed after the biological treatment and before the solid-liquid separation treatment.

4. The method for treating organic wastewater according to claim 2, characterized in that the excess sludge obtained in the solid-liquid separation treatment is returned to a treatment tank for biological treatment of the organic wastewater.

5. A method for treating organic wastewater according to any one of claims 1 to 4, characterized in that a bound and immobilized carrier that adheres or holds the microorganisms on its outer surface is used as the fluid carrier, and the carrier is introduced into the treatment tank in an amount of 1 to 50% by volume to perform the biological treatment.

6. The method for treating organic wastewater according to claim 5, characterized in that the biological treatment is performed such that, when the amount of sludge adhering to the fluid carrier at a certain point in time is taken as 100%, the rate of increase or decrease in the amount of sludge adhering to the fluid carrier two weeks after the aforementioned point in time is within 15%.

7. A conditioning means for introducing and storing organic wastewater containing chromatic components and recalcitrant organic substances with a fractional molecular weight of 500 or more, A fluid carrier housed within the adjustment means, The adjusting means includes a biological agent adding means for adding a biological agent containing iron ions, calcium ions, and water to obtain a biological agent treated solution, A biological treatment means for obtaining biologically treated water by introducing the biological activator treatment solution, bringing the fluid carrier into contact with the biological activator treatment solution, and attaching microorganisms to the fluid carrier so that the amount of sludge adhering to the fluid carrier is 5 to 60 mg-SS / unit, thereby removing the recalcitrant organic matter and the chromatic components, A coagulation treatment means for coagulating the aforementioned biologically treated water to obtain coagulated treated water, A solid-liquid separation means for separating the coagulated treated water into solid and liquid to obtain treated water, A treatment device for organic wastewater, characterized by comprising the following:

8. The apparatus for treating organic wastewater according to claim 7, further comprising a sludge return means for returning excess sludge obtained by the solid-liquid separation means to the adjustment means or the biological treatment means in an amount of 0.5 to 40% by volume relative to the raw water inflow.

9. The treatment apparatus for organic wastewater according to claim 7, characterized in that the biological activator adding means further adds the biological activator to the biological treatment means.

10. The apparatus for treating organic wastewater according to claim 7 or 8, characterized in that the biological treatment means uses a bound and immobilized carrier that adheres or holds the microorganisms on its outer surface as the fluid carrier, and the carrier is contained in the treatment tank at a volume of 5 to 50 percent to perform the biological treatment.

11. An agent for removing recalcitrant organic matter and color components from organic wastewater used in the method for treating organic wastewater according to any one of claims 1 to 4.

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