Microbial agent for removing refractory COD (Chemical Oxygen Demand) in wastewater and application of microbial agent

Abstract

The invention relates to a microbial agent for removing refractory COD (Chemical Oxygen Demand) in wastewater and application of the microbial agent, and belongs to the technical field of biological purification. The invention provides a microbial agent for removing refractory COD (Chemical Oxygen Demand) in wastewater. The microbial agent is prepared from two or more of geomonas, rope warming bacteria, nitro-spirillum, thiobacillus, urea bacillus, leptospirillum, piriformospora, floating fungi, nitro-spina bacteria, thauera and hyphomicrobe. The microbial agent can remove part of refractory COD (Chemical Oxygen Demand) by utilizing the synergistic effect and co-metabolism of biocenosis, and has a great application prospect in the treatment of wastewater (such as landfill leachate and the like) containing a large amount of refractory COD.

Description

Technical Field

[0001] The invention relates to a microbial agent for removing refractory COD in wastewater and application thereof, belonging to the technical field of biological purification. Background Art

[0002] Landfill leachate is a complex, high-concentration organic wastewater, whose properties depend on factors such as the waste composition, particle size, degree of compaction, site climate, hydrological conditions, and landfill age. Common leachate treatment methods include flocculation and sedimentation, nitrification / denitrification, activated sludge, membrane bioreactors (MBRs), nanofiltration (NF), reverse osmosis (RO), and mesophilic anaerobic treatment. Given the complexity and instability of leachate, a combination of these methods is often employed.

[0003] However, even after the combined approach, a significant amount of refractory COD remains in the leachate, typically between 500 and 3000 mg / L. Using traditional biological methods, the biodegradability of this refractory COD is already very low. To further reduce the refractory COD in leachate, the industry typically employs costly and energy-intensive processes such as adsorption and advanced oxidation. Developing a biological process for the removal of refractory COD could significantly reduce the operating costs and carbon emissions of treating refractory COD in leachate. Summary of the Invention

[0004] To solve the above problems, the present invention provides a microbial agent for removing refractory COD in wastewater, wherein the microbial agent includes two or more of the genera Terrimonas, Caldilinea, Nitrospira, Sulfobacillus, Ureibacillus, Leptospirillum, Pirellula, Planctomyces, Nitrospina, Thauera and Hyphomicrobium.

[0005] In one embodiment of the present invention, the microbial agent includes Terrestrial Mononas, Thermobacillus, Sulfobacillus, Leptospira and Ureabacillus; or, the microbial agent includes Nitrospira, Ureabacillus, Leptospira, Pyriformis and Hyphomicrobium.

[0006] In one embodiment of the present invention, when the microbial agent includes Terrestrial Mononas, Thermophila, Sulfobacillus, Leptospira, and Ureabacillus, the ratio of live bacteria of Terrestrial Mononas, Thermophila, Sulfobacillus, Leptospira, and Ureabacillus in the microbial agent is 1-2:3-4:1-2:1-3:3-5;

[0007] When the microbial agent includes Nitrospira, Urea Bacillus, Leptospira, Pyriformis and Mycobacterium, the live bacteria ratio of Nitrospira, Urea Bacillus, Leptospira, Pyriformis and Mycobacterium in the microbial agent is 1-3:3-5:2-4:3-4:2-3.

[0008] In one embodiment of the present invention, the Terrimonas genus includes one or more of Terrimonas lutea and Terrimonas ferruginea; the Caldilinea genus includes Caldilinea aerophila; the Nitrospira genus includes Nitrospira inopinata; the Sulfobacillus genus includes one or more of Sulfobacillus thermotolerans and Sulfobacillus acidophilus; the Ureibacillus genus includes Ureibacillus composti, Ureibacillus thermophilus, and Ureibacillus urea. thermophilus and Ureibacillus thermosphaericus; the genus Leptospirillum includes one or more of Leptospirillum ferrooxidans and Leptospirillum ferriphilum; the genus Pirellula includes one or more of Pirellula staleyi and Rhodopirellula baltica; the genus Planctomyces includes Planctomyces bekefii; the genus Nitrospina includes Nitrospinagracilis; the genus Thauera includes Thauera aminoaromatica; and the genus Hyphomicrobium includes Hyphomicrobium denitrificans.

[0009] In one embodiment of the present invention, the microbial agent is composed of Terromonas embellishii, Bacillus thermophilus, Bacillus thermophilus, Leptospira ferrooxidans, and Bacillus thermophilus, and in the microbial agent, the ratio of live bacteria of Terromonas embellishii, Bacillus thermophilus, Bacillus thermophilus, Leptospira ferrooxidans, and Bacillus thermophilus is 1-2:3-4:1-2:1-3:3-5;

[0010] Alternatively, the microbial agent is composed of full-process nitrifying bacteria, thermophilic urea bacillus, ferrooxidans Leptospirillum, Baltic red piriform bacteria and denitrifying filamentous microbes, and in the microbial agent, the live bacteria ratio of full-process nitrifying bacteria, thermophilic urea bacillus, ferrooxidans Leptospirillum, Baltic red piriform bacteria and denitrifying filamentous microbes is 1-3:3-5:2-4:3-4:2-3.

[0011] The present invention also provides a microbial filler for removing refractory COD in wastewater. The microbial filler is a carrier with a microbial flora colonized on the surface; the microbial flora is obtained by breeding the above-mentioned microbial agent on the surface of the carrier.

[0012] In one embodiment of the present invention, the microbial flora forms a biofilm on the carrier.

[0013] In one embodiment of the present invention, the preparation method of the microbial filler includes: mixing a microbial culture medium, a carrier and the above-mentioned microbial agent, and culturing them under aerobic conditions of 25 to 45° C. until the above-mentioned microbial agent multiplies on the surface of the carrier to form a biofilm, thereby obtaining a microbial filler.

[0014] In one embodiment of the present invention, the total viable count of the microbial agent in the microbial culture medium is 5×10 9 ~1×10 10 CFU / mL; the inoculation amount of the carrier in the microbial culture medium is 0.5-1g / mL.

[0015] In one embodiment of the present invention, the carrier includes one or more of an inorganic carrier and an organic carrier; the material of the inorganic carrier includes one or more of carbonate minerals, glass, zeolite minerals, ceramics, carbon fiber, slag, activated carbon and metals; the material of the organic carrier includes one or more of polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), resin, plastic, fiber and gelatin.

[0016] The present invention also provides a device for removing refractory COD in wastewater, which comprises a reactor filled with the above-mentioned microbial filler.

[0017] In one embodiment of the present invention, the reactor is a bioreactor; the inlet of the bioreactor is at the bottom and the outlet is at the top.

[0018] In one embodiment of the present invention, the microbial filler is loaded above the rectifying plate of the bioreactor.

[0019] In one embodiment of the present invention, the device further includes a water inlet pump, an air compressor and an air distributor; the water inlet pump is connected to the input port of the bioreactor through a pipeline, so that wastewater can be transported to the bioreactor through the water inlet pump; the air distributor is arranged below the rectifier plate of the bioreactor; the air compressor is connected to the air distributor through a pipeline, and is used to pressurize the air and transport it to the bioreactor (after the air is pressurized by the air compressor, it is evenly distributed in the reactor through the air distributor).

[0020] In one embodiment of the present invention, the device further comprises a reflux valve; the two ends of the reflux valve are respectively connected to the input port of the water inlet pump and the output port of the bioreactor through pipes, and are used to reflux the treated wastewater flowing out of the output port of the bioreactor as an external loop back to the bioreactor for secondary treatment.

[0021] In one embodiment of the present invention, the device consists of a wastewater storage tank, a water inlet pump, a bioreactor, a microbial filler, a rectifier plate, a reflux valve, an air compressor, an air distributor and pipes connecting the various parts; the microbial filler is loaded above the rectifier plate of the bioreactor; the inlet of the bioreactor is at the bottom and the outlet is at the top; the water inlet pump is connected to the lower inlet of the bioreactor through a pipe, so that the wastewater in the wastewater storage tank can be transported to the bioreactor through the water inlet pump; the air distributor is arranged below the rectifier plate of the bioreactor; the air compressor is connected to the air distributor through a pipe, and is used to pressurize the air and transport it to the bioreactor; one end of the reflux valve is connected to the pipe at the inlet of the water inlet pump, and the other end is connected to the pipe at the top outlet of the bioreactor, and is used to return the treated wastewater flowing out of the top outlet of the bioreactor to the bioreactor as an external circulation for secondary treatment.

[0022] The present invention also provides a method for removing refractory COD in wastewater, the method comprising: treating the wastewater using the above-mentioned microbial agent, the above-mentioned microbial filler or the above-mentioned device.

[0023] In one embodiment of the present invention, the method includes: transporting wastewater from the lower input port of the bioreactor to the bioreactor at an initial transport flow rate, gradually increasing the wastewater transport flow rate during the transport process, and observing the expansion of the biological filler and the fluid state in the bioreactor until the bed is completely fluidized; after the bed is completely fluidized, continuously transporting the wastewater to the bioreactor at a constant transport flow rate, controlling the hydraulic retention time of the wastewater in the bioreactor to 2.5 to 15 hours during the transport process, and controlling the dissolved oxygen content of the wastewater in the bioreactor to 3 to 5 mg / L; continuously operating the bioreactor to remove some of the difficult-to-degrade COD in the wastewater; the treated wastewater flows out from the top output port of the bioreactor, and the treated wastewater is divided into two parts after flowing out from the top output port of the bioreactor, one part of which is returned to the bioreactor as an external loop for secondary treatment, and the other part enters the next purification process as a product.

[0024] In one embodiment of the present invention, the bioreactor has a height-to-diameter ratio of 1:1 to 1:10, a bed pressure drop of 10% to 20%, and an external circulation volume of 0% to 60%.

[0025] In one embodiment of the present invention, the initial delivery flow rate is 0.01 to 0.5 m 3 / h; the speed increase of the delivery flow is 0.001~0.1m 3 / h; the constant delivery is 0.1~5m 3 / h.

[0026] In one embodiment of the present invention, the dissolved oxygen content of the wastewater in the bioreactor is controlled by adjusting the flow rate and pressure of the air compressor.

[0027] In one embodiment of the present invention, the hydraulic retention time of wastewater in the bioreactor is controlled by adjusting the opening of the water inlet pump and the valve.

[0028] The present invention also provides the use of the microbial agent, the microbial filler, the device or the method in removing refractory COD from wastewater.

[0029] In one embodiment of the present invention, the refractory COD value of the wastewater is between 100 and 3000 mg / L, and the BOD5 value is less than 50 mg / L.

[0030] The technical solution of the present invention has the following advantages:

[0031] 1. The present invention provides a microbial agent for removing refractory COD in wastewater, comprising two or more species selected from the genera Terrimonas, Caldilinea, Nitrospira, Sulfobacillus, Ureibacillus, Leptospirillum, Pirellula, Planctomyces, Nitrospina, Thauera, and Hyphomicrobium. The microbial agent can utilize the synergistic effect and cometabolism of biota to remove some refractory COD, and has great application prospects in the treatment of wastewater containing large amounts of refractory COD (e.g., landfill leachate).

[0032] Furthermore, the microbial agent includes Terromonas, Thermobacillus, Sulfobacterium, Leptospira, and Ureabacillus; or the microbial agent includes Nitrospira, Ureabacillus, Leptospira, Pyriformis, and Hyphomicrobium. This microbial agent has a better effect in removing refractory COD.

[0033] Furthermore, when the microbial agent includes Terromonas, Thermobacillus, Sulfobacillus, Leptospira, and Ureobacillus, the ratio of live bacteria of Terromonas, Thermobacillus, Sulfobacillus, Leptospira, and Ureobacillus in the microbial agent is 1-2:3-4:1-2:1-3:3-5; when the microbial agent includes Nitrospira, Ureobacillus, Leptospira, Pyriformis, and Hyphomicrobium, the ratio of live bacteria of Nitrospira, Ureobacillus, Leptospira, Pyriformis, and Hyphomicrobium in the microbial agent is 1-3:3-5:2-4:3-4:2-3. This microbial agent has a better effect in removing refractory COD.

[0034] 2. The present invention provides a method for removing refractory COD in wastewater, the method comprising: treating the wastewater using a device for removing refractory COD in wastewater; the device comprising a reactor filled with a microbial filler; the microbial filler is a carrier with a microbial flora colonized on the surface; the microbial flora is obtained by propagating a microbial agent on the surface of the carrier; the microbial agent comprises two or more of the genera Terrimonas, Caldilinea, Nitrospira, Sulfobacillus, Ureibacillus, Leptospirillum, Pirellula, Planctomyces, Nitrospina, Thauera and Hyphomicrobium. Reducing refractory COD in landfill leachate using biological methods requires overcoming the following challenges: Large fluctuations in wastewater quality, requiring robustness in both biological species and colonization patterns; and addressing the efficiency of the biological reaction. Otherwise, oversized reactors and excessive hydraulic retention times will lead to increased investment and operating costs, negating the advantages of biological methods. The core advantage of this invention lies in its adaptability to treating wastewater containing high levels of refractory COD, obtained after treating landfill leachate. First, for a certain target waste liquid, the composition of its difficult-to-degrade COD (such as molecular weight and atomic composition, etc.) will be within a certain range. The present invention screens out efficient microbial species and microbial symbionts based on the composition of COD, and selects biological fillers based on the selected microorganisms. In this way, suitable microorganisms quickly form dominant bacterial communities and symbionts on suitable biological fillers, absorb nutrients and cometabolize. At the same time, suitable biological fillers can protect microorganisms to resist the impact of waste liquid water quality fluctuations. Among them, the cometabolism between microorganisms can further improve the efficiency of biological reactions (cometabolism refers to the process in which microorganisms obtain most or all of the carbon source and energy from other substrates and degrade organic compounds in the same medium. In the presence of other carbon sources and energy, the activity of microbial enzymes is enhanced, and the efficiency of degrading non-growth substrates is improved, also known as cometabolism).

[0035] Furthermore, the method includes: delivering wastewater from the lower input port of the bioreactor to the bioreactor at an initial delivery flow rate, gradually increasing the delivery flow rate of the wastewater during the delivery process, and observing the expansion of the biological filler and the fluid state in the bioreactor until the bed layer is fully fluidized; after the bed layer is fully fluidized, continuously delivering the wastewater to the bioreactor at a constant delivery flow rate, and during the delivery process, controlling the hydraulic retention time of the wastewater in the bioreactor to 2.5 to 15 hours, and controlling the dissolved oxygen content of the wastewater in the bioreactor to 3 ~5mg / L; continuously operate the bioreactor to remove some of the refractory COD in the wastewater; the treated wastewater flows out from the top outlet of the bioreactor, and is divided into two parts after flowing out from the top outlet of the bioreactor, one part of which is returned to the bioreactor as an external circulation for secondary treatment, and the other part enters the next purification process as a product; the height-to-diameter ratio of the bioreactor is 1:1-1:10, the bed pressure drop is 10%-20%, and the external circulation volume is 0%-60%; the initial delivery flow rate is 0.01-0.5m 3 / h; the speed increase of the delivery flow is 0.001~0.1m 3 / h; the constant delivery is 0.1~5m 3 The present invention designs the specifications and processes of the reactor (such as height-to-diameter ratio and reflux rate, etc.) based on the processing volume of the waste liquid and the numerical range of the refractory COD, further improving the system's impact resistance and the efficiency of the biological reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 : Schematic diagram of the structure of a device for removing refractory COD in wastewater. Figure 1 In the figure, there are fermentation tank 10, microbial culture medium 11, carrier 12, microbial agent 13, wastewater storage tank 20, water inlet pump 21, bioreactor 22, microbial filler 23, rectifying plate 24, reflux valve 25, air compressor 30, and air distributor 31. DETAILED DESCRIPTION

[0037] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0038] If no specific experimental steps or conditions are specified in the following examples, the experiments were carried out according to the conventional experimental steps or conditions described in the literature in the field. If no manufacturer is specified for the reagents or instruments used, they are all commercially available conventional reagents.

[0039] In the following examples, the COD value of the target wastewater was detected with reference to HG / T 5964-2021 "Determination of the Content of Soluble Refractory COD in Wastewater". For target wastewater with a refractory COD value exceeding 1000 mg / L, the wastewater was diluted with deionized water and then tested according to the method provided in HG / T 5964-2021.

[0040] Example 1-1: A microbial agent for removing refractory COD in wastewater

[0041] This embodiment provides a microbial agent for removing refractory COD in wastewater, wherein the microbial agent is composed of Teratomonas erythrocyticus (purchased from the American Type Culture Collection, strain number ATCC13524), Pseudomonas thermophilus (purchased from the German Collection of Microorganisms, strain number DSM14535), Sulfolobus thermophilus (purchased from the German Collection of Microorganisms, strain number DSM17362), Leptospirillum ferrooxidans (purchased from the American Type Culture Collection, strain number ATCC 49879) and Ureabacillus thermophilus (purchased from the German Collection of Microorganisms, strain number DSM17952); in the microbial agent, the live bacteria ratio of Teratomonas erythrocyticus, Pseudomonas thermophilus, Pseudomonas thermophilus, Leptospirillum ferrooxidans and Ureabacillus thermophilus is 1:3:1:2:4 (the purchased bacterial solution is directly taken and compounded according to the live bacteria ratio).

[0042] Example 1-2: A microbial agent for removing refractory COD in wastewater

[0043] This embodiment provides a microbial agent for removing refractory COD in wastewater, wherein the microbial agent is composed of a complete nitrifying bacteria (purchased from the JCM Culture Collection, strain number JCM 31988), a thermophilic urea bacillus (purchased from the German Culture Collection of Microorganisms, strain number DSM17952), a ferrooxidans leptospirillum (purchased from the American Type Culture Collection, strain number ATCC 49879), a Baltic red piriform bacteria (purchased from the German Culture Collection of Microorganisms, strain number DSM10527), and a denitrifying hyphae microbacterium (purchased from the German Culture Collection of Microorganisms, strain number DSM1869); in the microbial agent, the live bacteria ratio of the complete nitrifying bacteria, the thermophilic urea bacillus, the ferrooxidans leptospirillum, the Baltic red piriform bacteria, and the denitrifying hyphae microbacterium is 1:3:3:4:2 (obtained by directly taking the purchased bacterial solution and compounding it according to the live bacteria ratio).

[0044] Example 2-1: A microbial filler for removing refractory COD in wastewater

[0045] This embodiment provides a microbial filler for removing refractory COD in wastewater, wherein the microbial filler is a carrier with a microbial flora colonized on the surface; the microbial flora is obtained by breeding the microbial agent of Example 1-1 on the surface of the carrier; the microbial flora forms a biofilm on the carrier.

[0046] The preparation method of the microbial filler comprises: Figure 1 As shown, in a fermentation tank 10, a microbial culture medium (0.5% glucose broth medium, ChP) 11, a carrier (activated carbon) 12, and the microbial agent 13 of Example 1-1 were mixed and cultured under aerobic conditions at 35°C for 10 days until the microbial agent of Example 1-1 multiplied and formed a biofilm on the surface of the carrier, thereby obtaining a microbial filler; wherein the total viable count of the microbial agent in the microbial culture medium was 9×10 9 CFU / mL; the inoculation amount of the carrier in the microbial culture medium is 2 g / mL, and aerobic conditions are achieved by introducing air 14 at a flow rate of 1000 mL / min.

[0047] After 10 days of culture, the carriers colonized with microbial flora were taken and the microorganisms attached to the surface of the carriers were peeled off by ultrasonic wave. The number of viable bacteria was greater than 2×10 8 CFU / g.

[0048] Example 2-2: A microbial filler for removing refractory COD in wastewater

[0049] This embodiment provides a microbial filler for removing refractory COD in wastewater. The microbial filler is obtained by replacing the microbial agent of Example 1-1 with the microbial agent of Example 1-2 on the basis of Example 2-1.

[0050] Example 3-1: A device for removing refractory COD from wastewater

[0051] like Figure 1As shown, this embodiment provides a device for removing refractory COD in wastewater, the device consists of a wastewater storage tank 20, a water inlet pump 21, a bioreactor 22 (a cylindrical reactor made of organic glass with an inner diameter of 300 mm), the microbial filler 23 of Example 2-1, a rectifier plate 24, a reflux valve 25, an air compressor 30, an air distributor 31 and pipes connecting the various parts; the microbial filler 23 is loaded above the rectifier plate 24 of the bioreactor 22 (static filler height 500 mm); the inlet of the bioreactor 22 is at the bottom and the outlet is at the top; the water inlet pump 21 is connected to the lower inlet of the bioreactor 22 through a pipe, so that the wastewater in the wastewater storage tank 20 is discharged. It can be transported to the bioreactor 22 through the water inlet pump 21; the air distributor 31 is arranged below the rectifier plate 24 of the bioreactor 22; the air compressor 30 is connected to the air distributor 31 through a pipeline, and is used to pressurize the air and transport it to the bioreactor 22 (after the air is pressurized by the air compressor 30, it is evenly distributed in the bioreactor 22 through the air distributor 31); one end of the reflux valve 25 is connected to the pipeline at the inlet of the water inlet pump 21, and the other end is connected to the pipeline at the top output port of the bioreactor 22, and is used to return the treated wastewater flowing out of the top output port of the bioreactor 22 to the bioreactor 22 as an external loop for secondary treatment and adjustment and optimization of relevant parameters.

[0052] Example 3-2: A device for removing refractory COD from wastewater

[0053] This embodiment provides a device for removing refractory COD in wastewater. The device is based on Example 3-1, except that the microbial filler in Example 2-1 is replaced by the microbial filler in Example 2-2.

[0054] Example 4-1: A method for removing refractory COD from wastewater

[0055] This embodiment provides a method for removing refractory COD from wastewater, using the apparatus of Example 3-1, as follows:

[0056] The wastewater was treated at 0.01m 3 The initial delivery flow rate of / h is delivered to the bioreactor from the lower inlet of the bioreactor. During the delivery process, the flow rate is 0.005m 3 / h and gradually increase the wastewater delivery rate, and observe the expansion of the biological filler and the fluid state in the bioreactor until the bed layer is fully fluidized. After the bed layer is fully fluidized, 3 / h constant delivery flow rate is used to continuously deliver the wastewater to the bioreactor. During the delivery process, the hydraulic retention time of the wastewater in the bioreactor is controlled to be 4h, and the dissolved oxygen content of the wastewater in the bioreactor is controlled to be 5mg / L; the bioreactor is continuously operated to remove some of the difficult-to-degrade COD in the wastewater. During the operation, the dissolved oxygen content of the wastewater in the bioreactor is controlled by adjusting the flow and pressure of the air compressor, and the hydraulic retention time of the wastewater in the bioreactor is controlled by adjusting the opening of the water inlet pump and the valve; the treated wastewater flows out from the top output port of the bioreactor, and the treated wastewater is divided into two parts after flowing out from the top output port of the bioreactor, one part of which is returned to the bioreactor as an external loop for secondary treatment (reflux ratio of 25%), and the other part is directly discharged.

[0057] Example 4-2: A method for removing refractory COD from wastewater

[0058] This embodiment provides a method for removing refractory COD in wastewater. The method is based on Example 4-1, uses the device of Example 3-2, and controls the hydraulic retention time of the wastewater in the bioreactor to 2.5 hours.

[0059] Experimental Example 1: Verification of the treatment effect of refractory COD in wastewater

[0060] Experiment 1: Using wastewater from a municipal project as the target wastewater, the municipal project's wastewater treatment process consisted of "sludge thermal hydrolysis + anaerobic digestion + plate and frame dehydration + chemical phosphorus removal + anaerobic ammonium oxidation and advanced oxidation." The quality of the wastewater after treatment using these processes is shown in Table 1. The project needed to further reduce the amount of refractory COD to lower operating costs. Proprietary equipment was used to measure the molecular weight of organic matter in the target wastewater. The results showed that 11% of the wastewater had a molecular weight (MW) greater than 20,000, 18% had a molecular weight between 1,000 and 20,000, 34% had a molecular weight between 500 and 1,000, 27% had a molecular weight between 300 and 500, and 10% had a molecular weight less than 300.

[0061] The target wastewater was treated using the method described in Example 4-1. The reaction was run continuously for 12 weeks. During this period, the wastewater treatment effect was tested every other week, and the values were calculated as weekly averages. The actual wastewater treatment effect is shown in Table 2. As shown in Table 2, when the target wastewater was treated using the method described in Example 4-1, a high and stable removal rate was maintained throughout the test period.

[0062] Experiment 2: Target wastewater was wastewater from a power plant project. The treatment process for the power plant project was "biochemical treatment + ultrafiltration (UF) + disc-tube reverse osmosis (DTRO). The quality of the wastewater after treatment using these processes is shown in Table 3. The project needed to further reduce the refractory COD content to lower operating costs. Proprietary equipment was used to measure the molecular weight of organic matter in the target wastewater. The results showed that 13% of the wastewater had a molecular weight (MW) greater than 20,000, 26% had a molecular weight between 1,000 and 20,000, 27% had a molecular weight between 500 and 1,000, 15% had a molecular weight between 300 and 500, and 19% had a molecular weight less than 300.

[0063] The target wastewater was treated using the method described in Example 4-2. The reaction was run continuously for 12 weeks. During this period, the wastewater treatment effect was tested every week, and the values were calculated as weekly averages. The actual wastewater treatment effects are shown in Tables 4 and 5. As shown in Tables 4 and 5, when the target wastewater was treated using the method described in Example 4-2, a high and stable removal rate was maintained throughout the test period.

[0064] Table 1 Wastewater quality

[0065] Serial number project unit scope Standard method 1 Refractory COD mg / L 532～976 HG / T5964-2021 2 BOD mg / L 32～49 HJ505-2009 3 TOC mg / L 161～309 HJ501-2009 4 Turbidity NTU 1.92～3.87 HJ1075-2019 5 Chloride ion (asCl) mg / L 2586～6851 GB / T11896-1989

[0066] Table 2 Wastewater treatment effect (influent COD unit: mg / L, effluent COD unit: mg / L, removal rate unit: %)

[0067] week 1 2 3 4 5 6 7 8 9 10 11 12 average value Influent COD 634 761 452 673 564 467 872 459 638 723 562 636 620 Outlet COD 260 327 240 350 254 215 366 179 287 311 230 293 279 Removal rate 59 57 47 48 55 54 58 61 55 57 59 54 55

[0068] Table 3 Wastewater quality

[0069] Serial number project unit scope Standard method 1 Refractory COD mg / L 89～195 HG / T5964-2021 2 BOD mg / L 19～45 HJ505-2009 3 <![CDATA[Ammonia nitrogen NH3-N]]> mg / L 19～65 HJ535-2009 4 Suspended solids SS mg / L 22～36 GB / T11901-1989

[0070] Table 4 Wastewater treatment effect (influent COD unit: mg / L, effluent COD unit: mg / L, removal rate unit: %)

[0071]

[0072]

[0073] Table 5 Wastewater treatment effect (influent COD unit: mg / L, effluent COD unit: mg / L, removal rate unit: %)

[0074] week 8 9 10 11 12 average value Influent COD 164 176 167 169 160 167.58 Outlet COD 46 38 45 37 42 41.92 Removal rate 71.95 78.41 73.05 78.11 73.75 74.98

[0075] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A microbial agent for removing refractory COD in wastewater, characterized in that: The microbial agent includes two or more of the genera Terrimonas, Caldilinea, Nitrospira, Sulfobacillus, Ureibacillus, Leptospirillum, Pirellula, Planctomyces, Nitrospina, Thauera and Hyphomicrobium.

2. The microbial agent according to claim 1, wherein The microbial agent includes the genera of Terrestrial Mononas, Thermobacillus, Sulfobacillus, Leptospira and Ureabacillus; or, the microbial agent includes the genera of Nitrospira, Ureabacillus, Leptospira, Pyriformis and Mycena.

3. The microbial agent according to claim 2, wherein When the microbial agent includes Terrestrial Mononas, Thermophila, Sulfobacillus, Leptospira, and Ureabacillus, the ratio of live bacteria of Terrestrial Mononas, Thermophila, Sulfobacillus, Leptospira, and Ureabacillus in the microbial agent is 1-2:3-4:1-2:1-3:3-5; When the microbial agent includes Nitrospira, Urea Bacillus, Leptospira, Pyriformis and Mycobacterium, the live bacteria ratio of Nitrospira, Urea Bacillus, Leptospira, Pyriformis and Mycobacterium in the microbial agent is 1-3:3-5:2-4:3-4:2-3.

4. The microbial agent according to any one of claims 1 to 3, characterized in that The Terrimonas genus includes one or more of Terrimonas lutea and Terrimonas ferruginea; the Caldilinea genus includes Caldilinea aerophila; the Nitrospira genus includes Nitrospira inopinata; the Sulfobacillus genus includes one or more of Sulfobacillus thermotolerans and Sulfobacillus acidophilus; the Ureibacillus genus includes one or more of Ureibacillus composti, Ureibacillus thermophilus, and Ureibacillus thermosphaericus; the Leptospirillum genus includes Leptospirillum ferrooxidans. ferrooxidans) and one or more of Leptospirllum ferriphilum; the genus Pirillula includes one or more of Pirillula staleyi and Rhodopirellula baltica; the genus Planctomyces includes Planctomyces bekefii; the genus Nitrospina includes Nitrospina gracilis; the genus Thauera includes Thauera aminoaromatica; and the genus Hyphomicrobium includes Hyphomicrobium denitrificans.

5. The microbial agent according to any one of claims 1 to 4, characterized in that The microbial agent is composed of Terromonas erythrochromis, Bacillus thermophilus, Bacillus thermophilus, Leptospirillum ferrooxidans and Bacillus thermophilus, and the ratio of live bacteria of Terromonas erythrochromis, Bacillus thermophilus, Bacillus thermophilus, Leptospirillum ferrooxidans and Bacillus thermophilus in the microbial agent is 1-2:3-4:1-2:1-3:3-5; Alternatively, the microbial agent is composed of full-process nitrifying bacteria, thermophilic urea bacillus, ferrooxidans Leptospirillum, Baltic red piriform bacteria and denitrifying filamentous microbes, and in the microbial agent, the live bacteria ratio of full-process nitrifying bacteria, thermophilic urea bacillus, ferrooxidans Leptospirillum, Baltic red piriform bacteria and denitrifying filamentous microbes is 1-3:3-5:2-4:3-4:2-3.

6. A microbial filler for removing refractory COD in wastewater, characterized in that: The microbial filler is a carrier with a microbial flora colonized on the surface; the microbial flora is obtained by breeding the microbial agent according to any one of claims 1 to 5 on the surface of the carrier.

7. A device for removing refractory COD from wastewater, characterized in that: The device comprises a reactor filled with the microbial filler according to claim 6.

8. A method for removing refractory COD in wastewater, characterized in that: The method comprises: treating wastewater using the microbial agent according to any one of claims 1 to 5, the microbial filler according to claim 6, or the device according to claim 7.

9. The method according to claim 8, wherein The method comprises: delivering wastewater from a lower input port of a bioreactor to the bioreactor at an initial delivery flow rate, gradually increasing the delivery flow rate of the wastewater during the delivery process, and observing the expansion of biological fillers and the fluid state in the bioreactor until the bed layer is completely fluidized; after the bed layer is completely fluidized, continuously delivering the wastewater to the bioreactor at a constant delivery flow rate, controlling the hydraulic retention time of the wastewater in the bioreactor to be 2.5 to 15 hours, and controlling the dissolved oxygen content of the wastewater in the bioreactor to be 3 to 5 mg / L during the delivery process; continuously operating the bioreactor to remove part of the refractory COD in the wastewater; and the treated wastewater flows out from a top output port of the bioreactor. After flowing out from the top output port of the bioreactor, the treated wastewater is divided into two parts, one part of which is returned to the bioreactor as an external circulation for secondary treatment, and the other part enters the next purification process as a product.

10. Use of the microbial agent according to any one of claims 1 to 5, the microbial filler according to claim 6, the device according to claim 7, or the method according to claim 8 or 9 in removing refractory COD from wastewater.

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