Multi-stage and multi-phase microbial denitrification method and denitrification device

Abstract

The invention belongs to the technical field of wastewater denitrification, and particularly relates to a multi-stage and multi-phase microbial denitrification method and denitrification device. The multi-stage and multi-phase microbial denitrification method provided by the invention comprises the following steps: sequentially treating wastewater through a short-cut denitrification process, a short-cut nitrification process, an anaerobic ammonia oxidation process, a Fenton oxidation process and a sulfur autotrophic denitrification process, wherein nitrification liquid of the short-cut nitrification process flows back to the short-cut denitrification process. Nitrogen pollutants in the wastewater are converted into nitrogen through short-cut denitrification, short-cut nitrification, anaerobic ammonia oxidation, Fenton oxidation and sulfur autotrophic denitrification, pollutants such as COD, NH3-N, TN and intractable organic nitrogen in the wastewater can be degraded at the same time, and the total nitrogen removal rate is increased while the high COD removal rate is kept.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater denitrification, and in particular to a multi-stage multi-phase microbial denitrification method and a denitrification device. Background Art

[0002] Brewing wastewater contains a large amount of organic pollutants, especially ammonia nitrogen and total nitrogen. If it is discharged directly into the nature without treatment, it will cause serious harm to the environment and human health. Traditional wastewater denitrification mostly uses autotrophic nitrification and heterotrophic denitrification microbial technology. The reaction process requires a lot of aeration and relies on the addition of external carbon sources. Not only is the treatment efficiency low and energy consumption high, but the effluent has a high concentration of residual dissolved organic nitrogen, which affects the discharge and recycling of wastewater, and produces a large amount of secondary pollutants such as residual sludge.

[0003] In recent years, short-range nitrification and denitrification-anaerobic ammonium oxidation technology has gradually attracted attention due to its advantages such as low aeration volume, no need to add carbon source and small amount of residual sludge. Anaerobic ammonium oxidation can react with nitrite nitrogen to generate nitrogen gas under anaerobic conditions, using ammonia nitrogen as an electron donor.

[0004] The Chinese patent with the authorization announcement number CN106966498B authorized for public disclosure on April 17, 2020 discloses a short-term nitrification and denitrification coupled anaerobic ammonia oxidation denitrification process and control method. The SBBR reactor filled with porous sponge can realize short-term nitrification, denitrification and anaerobic ammonia oxidation in one reactor at the same time. Through the control of the reactor and operating conditions, ammonia oxidizing bacteria and denitrifying bacteria first undergo short-term nitrification and denitrification in the outer layer of the biofilm. As the substrate enters the inner layer of the biofilm, the remaining part of the ammonia nitrogen and nitrite undergoes anaerobic ammonia oxidation under the action of anaerobic ammonia oxidizing bacteria to achieve autotrophic nitrogen removal, which can effectively treat wastewater containing high concentrations of COD and ammonia nitrogen. The process has high denitrification and carbon removal efficiency, with a COD removal rate of more than 90% and a total nitrogen TN removal rate of 80-85%, and can effectively treat wastewater with a medium C / N ratio (2~5).

[0005] However, the above denitrification method has a TN removal efficiency of only 80-85%, and the TN removal efficiency is low. Summary of the invention

[0006] The object of the present invention is to provide a multi-stage multi-phase microbial denitrification method to solve the problem of poor total nitrogen removal efficiency of existing denitrification methods.

[0007] The second object of the present invention is to provide a multi-stage multi-phase microbial denitrification device to solve the problem of poor total nitrogen removal efficiency of existing denitrification devices.

[0008] In order to solve the above technical problems, the technical solution of the multi-stage multi-phase microbial denitrification method of the present invention is: A multi-stage multi-phase microbial denitrification method comprises the following steps: treating wastewater in sequence through a short-cut denitrification process, a short-cut nitrification process, an anaerobic ammonia oxidation process, a Fenton oxidation process, and a sulfur autotrophic denitrification process, and the nitrified liquid of the short-cut nitrification process is refluxed to the short-cut denitrification process.

[0009] The present invention is an improvement on the prior art, and provides a multi-stage multi-phase microbial denitrification method. The denitrification principle is as follows: (1) The wastewater is firstly subjected to a pre-short-term denitrification process + a short-term nitrification process. Under the action of short-term denitrification microorganisms, the organic matter in the wastewater is used as a carbon source to provide electron donors for denitrifying bacteria, thereby converting nitrite into nitrogen gas. Under the action of short-term nitrification microorganisms, ammonia nitrogen is oxidized into nitrite, and then the generated nitrite is reduced to nitrogen gas by reflux through denitrification, thereby achieving the simultaneous removal of TN and COD, and regulating the ratio of residual ammonia nitrogen and nitrite in the effluent. Example 1: (1~1.2) so that it can be used as the raw material for the next anaerobic ammonium oxidation process; (2) then through the anaerobic ammonium oxidation process, with ammonia nitrogen as the electron donor and nitrite as the electron acceptor, the ammonia nitrogen and nitrite nitrogen are converted into nitrogen gas through anaerobic ammonium oxidation; (3) then through the Fenton oxidation process, the residual COD and refractory organic nitrogen in the wastewater are mineralized and produce nitrate nitrogen under the action of hydroxyl free radicals produced by hydrogen peroxide catalyzed by the catalyst; (4) finally, through the sulfur autotrophic denitrification process, the nitrate nitrogen is reduced to nitrogen gas by the action of sulfur autotrophic denitrifying bacteria, thereby achieving efficient denitrification of the wastewater.

[0010] The present invention integrates the application of heterotrophic and autotrophic microbial denitrification processes, fully utilizes the organic matter in the wastewater itself and the sulfur in the sulfur autotrophic filler as the microbial carbon source and sulfur source respectively, and simultaneously degrades pollutants such as COD, NH3-N, TN and difficult-to-degrade stubborn organic nitrogen in the wastewater, thereby achieving low energy consumption, low carbon source, high precision and resource utilization in the deep denitrification process of high-ammonia nitrogen industrial wastewater, providing new technical support for the deep purification and safe recycling of wastewater.

[0011] The present invention combines a pre-short-term denitrification process with a short-term nitrification process, which not only solves the problem that an additional carbon source needs to be added for denitrification, but also provides alkalinity for the short-term nitrification process, greatly reducing the supplement of alkalinity in the short-term nitrification process, and utilizes organic matter in the raw wastewater to remove nitrates produced by short-term nitrification and reduce the influence of COD on the anaerobic ammonium oxidation process; the short-term nitrification and denitrification stably provides the necessary electron donors and electron acceptors for anaerobic ammonium oxidation, ensuring the efficient and stable operation of the anaerobic ammonium oxidation process, and improving the treatment efficiency and system stability.

[0012] The multi-stage multi-phase microbial denitrification method provided by the present invention can control the aeration volume at 200-300 ml / min. The overall process reduces the oxygen demand by 60% compared with the traditional wastewater denitrification technology (nitrification and denitrification). Oxidation of 1g of total nitrogen can save 4.57g of oxygen. No external carbon source is required, and the overall process has a total nitrogen TN removal rate of more than 96%, and the total nitrogen TN removal load is as high as 0.15kgTN / m 3 / d, which is much higher than the 0.06kgTN / m of the traditional A / O denitrification process (using heterotrophic denitrification process). 3 / d, the lowest TN concentration in the effluent can reach 2 mg / L, and the COD removal rate can reach 90%. While maintaining a high COD removal rate, the TN removal rate can be greatly improved.

[0013] In order to further improve the effective conversion of nitrogen in the short-range nitrification and short-range denitrification processes, preferably, the reflux ratio of the nitrification solution is 200-300%.

[0014] By precisely controlling the temperature, pH value and dissolved oxygen concentration of bacteria in different processes, the denitrification effect can be optimized and graded cultivation of microorganisms can be achieved.

[0015] Preferably, the dissolved oxygen concentration in the short-cut denitrification process is 0.05-0.2 mg / L, the dissolved oxygen concentration in the short-cut nitrification process is 0.35-2.0 mg / L, the dissolved oxygen concentration in the anaerobic ammonia oxidation process is 0.1-0.2 mg / L, and the dissolved oxygen concentration in the sulfur autotrophic denitrification process is less than 0.2 mg / L.

[0016] Preferably, the pH in the short-cut denitrification process, the short-cut nitrification process and the anaerobic ammonium oxidation process is 7.8-8.3; the pH in the sulfur autotrophic denitrification process is 6.3-8.0.

[0017] Preferably, the temperature of the short-cut denitrification process, the short-cut nitrification process, the anaerobic ammonia oxidation process, and the sulfur autotrophic denitrification process is 30-35°C.

[0018] In order to further improve the catalytic efficiency of the Fenton oxidation process and realize waste utilization, preferably, the catalyst used in the Fenton oxidation process is an activated carbon-supported iron-based catalyst; the sulfur autotrophic filler used in the sulfur autotrophic denitrification process is a mixture of sulfur-containing excess sludge produced by biogas biological desulfurization and ceramsite and limestone and then granulated, the sulfur content of the sulfur-containing excess sludge is 32~40%, and the volume ratio of the sulfur-containing excess sludge to ceramsite and limestone is (1~2): (1~2): (1~2). In the sulfur autotrophic denitrification process, the sulfur autotrophic filler made of sulfur-containing excess sludge produced by biogas biological desulfurization is used as an electron donor and nitrate nitrogen as an electron acceptor to complete the efficient removal of nitrate nitrogen in the system, effectively realizing the waste utilization of excess sludge in the biogas desulfurization unit and improving the treatment efficiency. It can be understood that the activated carbon-supported iron-based catalyst is a conventional catalyst used in the Fenton oxidation process, specifically obtained by impregnating activated carbon with ferrous sulfate solution and then roasting.

[0019] In order to further improve the denitrification efficiency, preferably, the initial sludge concentration in the short-cut denitrification process and the sulfur autotrophic denitrification process is not less than 4500 mg / L, the initial sludge concentration in the short-cut nitrification process is 2000~3000 mg / L, and the initial sludge concentration in the anaerobic ammonia oxidation process is 400~500 mg / L.

[0020] The technical solution of the multi-stage multi-phase microbial denitrification device of the present invention is: A multi-stage multi-phase microbial denitrification device comprises a short-cut denitrification tank, a short-cut nitrification tank, an anaerobic ammonia oxidation tank, a Fenton oxidation tank, and a sulfur autotrophic denitrification tank connected in series; the short-cut nitrification tank is connected to the water inlet pipe of the short-cut denitrification tank through a reflux pipe, so as to return the nitrified liquid in the short-cut nitrification tank to the short-cut denitrification tank.

[0021] The denitrification device provided by the present invention connects multiple biological reaction tanks in series, and adopts the multi-stage multi-phase microbial denitrification method to sequentially perform denitrification treatment of wastewater through a short-range denitrification process - a short-range nitrification process - an anaerobic ammonia oxidation process - a Fenton oxidation process - a sulfur autotrophic denitrification process, which can simultaneously degrade pollutants such as COD, NH3-N, TN and difficult-to-degrade stubborn organic nitrogen in the wastewater, and greatly improve the total nitrogen TN removal rate while maintaining a high COD removal rate.

[0022] In order to further achieve hierarchical regulation of microbial strains, preferably, the upper side walls of the short-range denitrification tank, short-range nitrification tank, anaerobic ammonia oxidation tank, and Fenton oxidation tank are all provided with a precipitator for mud-water separation, and the precipitator is provided with a water outlet, and two adjacent biological treatment tanks are connected through the water outlet to achieve the series connection of each biological treatment tank. By setting a separate precipitator in the biological treatment tank, the sludge return and mud-water separation functions are integrated into one, without the need to set up an additional sedimentation tank, effectively intercepting functional bacteria, and realizing the separate cultivation of microorganisms at each level, and by accurately controlling the pH, temperature, dissolved oxygen concentration, etc. at each level, a multi-phase and multi-level microbial reaction zone is realized.

[0023] In order to further improve the mud-water separation efficiency, preferably, the settler includes a support frame having an internal cavity, the support frame is provided with a water inlet and a water outlet, and the internal cavity of the support frame is provided with a plurality of parallel inclined plates at a position located between the water inlet and the water outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of a multi-stage multi-phase microbial denitrification device according to Example 1 of the present invention; Figure 2 for Figure 1 Structural schematic diagram of the inclined plate sedimentation tank; Figure 3 This is a graph showing the test results of the effluent water quality after being treated by the denitrification method according to Example 2 of the present invention; Figure 4 This is a graph showing the test results of effluent water quality after raw water with different concentrations is treated with the denitrification method of Example 2 of the present invention; In the attached figure: 1. Short-range denitrification tank; 2. Sedimentation vessel; 3. Short-range nitrification tank; 4. Anaerobic ammonia oxidation tank; 5. Fenton oxidation tank; 6. Sulfur autotrophic denitrification tank; 7. Water inlet pipe; 8. First stirring device; 9. Reflux pipe; 10. Reflux pump; 11. First aeration device; 12. Suspended filler; 13. Second stirring device; 14. Second aeration device; 15. Automatic control sensor; 16. Sulfur autotrophic filler; 17. Water outlet pipe; 18. Inclined plate; 19. Water outlet; 20. Support frame. DETAILED DESCRIPTION

[0025] The technical concept of the multi-stage multi-phase microbial denitrification method of the present invention is as follows: The existing short-term nitrification and denitrification-anaerobic ammonium oxidation technology uses short-term nitrification and denitrification technology to first control ammonia nitrogen (NH4 + ) is oxidized to nitrite (NO2 - ), and then use denitrification to reduce nitrite to nitrogen gas under the condition of organic matter as carbon source. Anaerobic ammonium oxidation technology uses ammonia nitrogen as electron donor and nitrite as electron acceptor to convert nitrite into nitrogen gas and nitric acid.

[0026] However, the anaerobic ammonium oxidation effluent contains high levels of organic nitrogen and residual nitrate. The sulfur autotrophic denitrification technology can reduce nitrate or nitrite to nitrogen gas by using sulfur or sulfide as electron donors without adding an organic carbon source. The present invention uses wastewater organic matter as a carbon source to convert ammonia nitrogen and nitrite into nitrogen gas through pre-short-term denitrification + short-term nitrification, and can adjust the ratio of residual ammonia nitrogen and nitrite, and then convert ammonia nitrogen and nitrite nitrogen into nitrogen gas through anaerobic ammonia oxidation technology, and then convert residual COD and recalcitrant organic nitrogen into nitrate nitrogen through Fenton oxidation technology, and finally reduce nitrate nitrogen to nitrogen gas through sulfur autotrophic denitrification technology, so as to integrate a variety of high-efficiency nitrogen removal processes into one, and convert nitrogen pollutants in wastewater into nitrogen gas through short-term denitrification + short-term nitrification - anaerobic ammonia oxidation - Fenton oxidation - sulfur autotrophic denitrification, and can simultaneously degrade pollutants such as COD, NH3-N, TN and recalcitrant organic nitrogen that is difficult to degrade in wastewater, and can greatly improve the total nitrogen TN removal rate (more than 96%) and reduce the effluent organic nitrogen concentration while maintaining a high COD removal rate (90%).

[0027] The multi-stage multi-phase microbial denitrification method provided by the present invention comprises the following steps: the wastewater is treated in sequence by a short-range denitrification process, a short-range nitrification process, an anaerobic ammonia oxidation process, a Fenton oxidation process, and a sulfur autotrophic denitrification process, and the nitrified liquid of the short-range nitrification process is refluxed to the short-range denitrification process.

[0028] In a specific embodiment, the sulfur autotrophic denitrification tank is filled with sulfur autotrophic filler, and the total filling amount of the sulfur autotrophic filler and sludge is one third to one half of the volume of the sulfur autotrophic denitrification tank.

[0029] In a specific implementation, the sulfur-containing residual sludge produced by biogas biological desulfurization is compressed before the mixing; the particle size of the particles after the granulation is 2-5 mm; and the granulation is dried at room temperature for 12-14 hours.

[0030] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments are only helpful for those skilled in the art to further understand the present invention and are not intended to limit the scope of the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can be made, but these improvements and modifications should also belong to the protection scope of the present invention.

[0031] The preparation methods, materials, structures and other features not explicitly described in the present invention are deemed to be common technical features disclosed in the prior art.

[0032] Unless otherwise specified, the reagents and materials used in the following examples can be obtained from regular commercial channels or by known methods.

[0033] It should be noted that, in the present invention, terms such as “first”, “second”, “first”, “second”, “third”, etc. are only used for descriptive purposes and are not meant to indicate or imply relative importance.

[0034] 1. Specific embodiments of the multi-stage multi-phase microbial denitrification device of the present invention Example 1 The multi-stage multi-phase microbial denitrification device of this embodiment is as follows: Figure 1 As shown, it includes a short-distance denitrification tank 1, a short-distance nitrification tank 3, an anaerobic ammonia oxidation tank 4, a Fenton oxidation tank 5, and a sulfur autotrophic denitrification tank 6 connected in series; a water inlet pipe 7 is provided on the side wall of the short-distance denitrification tank 1; the short-distance denitrification tank 3 is connected to the water inlet pipe 7 of the short-distance nitrification tank 1 through a return pipe 9, and the return pipe 9 is provided with a return pump 10 for returning the nitrified liquid in the short-distance nitrification tank 1 to the short-distance denitrification tank 3; a water outlet pipe 17 is provided on the side wall of the sulfur autotrophic denitrification tank 6.

[0035] The upper side walls of the short-cut denitrification tank 1, the short-cut nitrification tank 3, the anaerobic ammonia oxidation tank 4, and the Fenton oxidation tank 5 are all provided with a precipitator 2. The structure of the precipitator 2 is as follows: Figure 2 As shown, the precipitator 2 includes a support frame 20 having an internal cavity and a plurality of inclined plates 18 arranged in parallel in the internal cavity of the support frame 20, and a water outlet 19 is provided on the side wall of the precipitator 2 located above the inclined plate 18. A water inlet (not shown) is provided on the left side wall of the support frame 20 located below the inclined plate 18, and the effluent of each biological treatment tank enters the precipitator 2 from the water inlet of the side wall of the support frame 20 and passes through the inclined plate 18. The sludge is deposited on the support frame 20 under the action of gravity and flows back to the biological treatment tank from the lower notch of the support frame 20, and the clean water enters the next biological treatment tank from the water outlet 19 of the precipitator 2 through the clean water area above the inclined plate 18. Each biological treatment tank connected in series passes the effluent of the previous treatment tank into the next treatment tank through the water outlet 19 of the precipitator 2.

[0036] The short-cut denitrification tank 1 and the anaerobic ammonium oxidation tank 4 are respectively provided with a first stirring device 8 and a second stirring device 13, and the anaerobic ammonium oxidation tank 4 is dispersed with a suspended filler 12; the short-cut nitrification tank 3 and the Fenton oxidation tank 5 are respectively provided with a first aeration device 11 and a second aeration device 14 at the bottom; the Fenton oxidation tank 5 is provided with an automatic sensor 15 on the side wall of the clear water area above the inclined plate 18 of the precipitator 2, which is used to monitor the nitrogen concentration and the pH value of the effluent, and the Fenton oxidation tank 5 is provided with an automatic sensor 15 at the outlet 19 of the precipitator 2 of the anaerobic ammonium oxidation tank 4, which is used to detect the nitrogen concentration and the pH value of the influent of the Fenton oxidation tank 5.

[0037] 2. Specific embodiments of the multi-stage multi-phase microbial denitrification method of the present invention Example 2 This embodiment uses the denitrification device of Example 1 to perform multi-stage multi-phase microbial denitrification, and the specific method is as follows: Take the anaerobic effluent of actual brewing wastewater with low concentration, and after pretreatment, the wastewater enters the short-distance denitrification tank 1 through the water inlet pipe 7, and the effluent of the short-distance denitrification tank 1 enters the short-distance nitrification tank 3 through the sedimentation tank 2. The nitrified liquid in the short-distance nitrification tank 3 flows back to the short-distance denitrification tank 1 through the reflux pipe 9, and the nitrified liquid reflux ratio is 220%. The wastewater and sludge are mixed through the first stirring device 8 in the short-distance denitrification tank 1, and the reaction is fully carried out through the first aeration device 11 in the short-distance nitrification tank 3. Under the action of short-distance denitrification microorganisms, the organic matter of the wastewater itself is used as a carbon source to provide electron donors for denitrification bacteria, and nitrite is converted into nitrogen gas. Under the action of chemical microorganisms, ammonia nitrogen is oxidized into nitrite, and then the generated nitrite is reduced to nitrogen gas by denitrification through reflux, so as to achieve the simultaneous removal of TN and COD, so that the ratio of residual ammonia nitrogen and nitrite in the effluent of the short-cut nitrification tank 3 is 1: (1-1.2), so as to serve as the raw material for the next step of anaerobic ammonium oxidation process; if the ratio of residual ammonia nitrogen and nitrite is not within the range of 1: (1-1.2), the aeration volume is adjusted within the range of 200-300 ml / min to control the ratio of residual ammonia nitrogen and nitrite within the range. If the ratio is too low, the aeration volume is increased, and if the ratio is too high, the aeration volume is reduced.

[0038] The effluent after the short-range nitrification tank 3 enters the anaerobic ammonia oxidation tank 4 through the outlet 19 of the sedimentator 2. The anaerobic ammonia oxidation tank 4 is provided with a suspended filler 12 and a stirring device 13. The sewage and sludge are mixed by the stirring device 13. The suspended filler 12 is a 1cm*1cm*1cm activated carbon composite cotton (BIOZYM). The suspended filler 12 reduces the loss of sludge and increases the attachment area of ​​microorganisms. In the anaerobic ammonia oxidation tank 4, ammonia nitrogen is used as an electron donor and nitrite is used as an electron acceptor. Ammonia nitrogen and nitrite nitrogen are converted into nitrogen gas through anaerobic ammonia oxidation.

[0039] The effluent from the anaerobic ammonia oxidation tank 4 enters the Fenton oxidation tank 5. The second aeration device 14 of the Fenton oxidation tank 5 allows the catalyst / hydrogen peroxide to fully react with the wastewater. The residual COD and recalcitrant organic nitrogen in the wastewater are mineralized and produce nitrate nitrogen under the action of hydroxyl free radicals produced by the catalyst-catalyzed hydrogen peroxide; the automatic sensor 15 located on the left side of the Fenton oxidation tank 5 can monitor the nitrogen concentration and pH of the influent, mainly to detect the ammonia nitrogen concentration of the influent, and control the nitrogen concentration within 5 mg / L by controlling the water inlet of the denitrification device; the automatic sensor 15 located on the right side of the Fenton oxidation tank 5 can monitor the nitrogen concentration and pH of the effluent, mainly to monitor the pH, and control the effluent pH to be neutral by adding acid and alkali in the Fenton oxidation tank 5, and at the same time detect the nitrogen concentration within 5 mg / L.

[0040] The effluent from the Fenton oxidation tank 5 enters the sulfur autotrophic denitrification tank 6. The sulfur autotrophic filler 16 filled in the sulfur autotrophic denitrification tank 6 is a mixture of sulfur-containing residual sludge produced by biogas biological desulfurization, ceramsite and limestone in a volume ratio of 1:1:1 and then granulated. The particle size of the sulfur autotrophic filler 16 is 2-5 mm. The total filling amount of the sulfur autotrophic filler 16 and the sludge is one third of the volume of the sulfur autotrophic denitrification tank 6. Nitrate nitrogen is reduced to nitrogen gas by the action of sulfur autotrophic denitrifying bacteria.

[0041] The sludge in the short-cut denitrification tank 1 and the sulfur autotrophic denitrification tank 6 is taken from the anaerobic tank sludge of the activated sludge system of the industrial sewage treatment plant, and the initial sludge concentration is not less than 4500 mg / L; the sludge in the short-cut nitrification tank 3 is derived from the aerobic tank sludge of the activated sludge system of the industrial sewage treatment plant, and the initial sludge concentration is 2000 mg / L; the sludge in the anaerobic ammonia oxidation tank 4 is taken from the sludge of the pilot anaerobic ammonia oxidation section of the sewage treatment plant, which is specially used to domesticate and maintain efficient anaerobic ammonia oxidation microbial communities, and the initial sludge concentration is 400 mg / L.

[0042] The dissolved oxygen concentration of the short-cut denitrification tank 1 is 0.05~0.2 mg / L, the dissolved oxygen concentration of the short-cut nitrification tank 3 is 0.35~2.0 mg / L, the dissolved oxygen concentration of the anaerobic ammonia oxidation tank 4 is 0.1~0.2 mg / L, and the dissolved oxygen concentration of the sulfur autotrophic denitrification tank 6 is less than 0.2 mg / L.

[0043] The pH value of the short-cut denitrification tank 1, the short-cut nitrification tank 3, and the anaerobic ammonium oxidation tank 4 is 7.8~8.3, and the pH value of the sulfur autotrophic denitrification tank 6 is 6.3~8.0; the temperature of the short-cut denitrification tank 1, the short-cut nitrification tank 3, the anaerobic ammonium oxidation tank 4, and the sulfur autotrophic denitrification tank 6 is 30°C.

[0044] The test results of the effluent water quality after the anaerobic effluent of low-concentration actual brewery wastewater was treated are as follows Figure 3 As shown, Figure 3 It can be seen that the nitrogen concentration of the anaerobic effluent (i.e. raw water) of low-concentration actual brewing wastewater is between 100 and 150 mg / L, and the COD concentration is between 200 and 400 mg / L. After 32 days of operation, the COD removal rate can reach 90.1%, and the total nitrogen removal rate can reach up to 98.2%. The lowest total nitrogen concentration in the effluent can reach 2 mg / L, and the ammonia nitrogen removal rate can reach 98.8%. The effluent does not contain nitrate nitrogen, and the total nitrogen removal load can reach 0.08 kg / m³ / d.

[0045] Starting from the 33rd day, the anaerobic effluent of actual brewery wastewater with a higher concentration was added for treatment. The test results of the treated effluent water quality are as follows: Figure 4As shown, the actual anaerobic effluent nitrogen concentration of brewing wastewater with higher concentration is 170~450mg / L, and the COD concentration is 370~900mg / L. During the 33rd-80th day, the ammonia nitrogen removal efficiency is 98.2% on average, and the total nitrogen removal rate is 96.3% on average, with a maximum of 98.8%. The lowest effluent total nitrogen concentration is 2.8mg / L, the COD removal rate is 89.9% on average, with a maximum of 95.5%, and the total nitrogen removal load can reach 0.15kg / m³ / d.

[0046] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. For ordinary technical personnel in this technical field, simple modifications or equivalent replacements of the technical solution of the present invention fall within the scope of protection of the present invention.

Claims

1. A multi-stage multi-phase microbial denitrification method, characterized in that: The following steps are involved: The wastewater is treated in sequence through a short-cut denitrification process, a short-cut nitrification process, an anaerobic ammonia oxidation process, a Fenton oxidation process, and a sulfur autotrophic denitrification process, and the nitrified liquid of the short-cut nitrification process is refluxed to the short-cut denitrification process.

2. The multi-stage multi-phase microbial denitrification method according to claim 1, characterized in that: The reflux ratio of the nitrifying solution is 200-300%.

3. The multi-stage multi-phase microbial denitrification method according to claim 1, characterized in that: The dissolved oxygen concentration in the short-cut denitrification process is 0.05-0.2 mg / L, the dissolved oxygen concentration in the short-cut nitrification process is 0.35-2.0 mg / L, the dissolved oxygen concentration in the anaerobic ammonia oxidation process is 0.1-0.2 mg / L, and the dissolved oxygen concentration in the sulfur autotrophic denitrification process is less than 0.2 mg / L.

4. The multi-stage multi-phase microbial denitrification method according to claim 1, characterized in that: The pH in the short-cut denitrification process, the short-cut nitrification process and the anaerobic ammonium oxidation process is 7.8-8.3; the pH in the sulfur autotrophic denitrification process is 6.3-8.

0.

5. The multi-stage multi-phase microbial denitrification method according to claim 1, characterized in that: The temperature of the short-range denitrification process, the short-range nitrification process, the anaerobic ammonia oxidation process, and the sulfur autotrophic denitrification process is 30-35°C.

6. The multi-stage multi-phase microbial denitrification method according to claim 1, characterized in that: The catalyst used in the Fenton oxidation process is an activated carbon-supported iron-based catalyst; the sulfur autotrophic filler used in the sulfur autotrophic denitrification process is a mixture of sulfur-containing excess sludge produced by biogas biological desulfurization, expanded clay and limestone, and the sulfur content of the sulfur-containing excess sludge is 32-40%, and the volume ratio of the sulfur-containing excess sludge to expanded clay and limestone is (1-2): (1-2): (1-2).

7. The multi-stage multi-phase microbial denitrification method according to claim 1, characterized in that: The initial sludge concentration in the short-cut denitrification process is not less than 4500 mg / L, the initial sludge concentration in the short-cut nitrification process is 2000-3000 mg / L, and the initial sludge concentration in the anaerobic ammonium oxidation process is 400-500 mg / L.

8. A multi-stage multi-phase microbial denitrification device, characterized in that: It comprises a short-cut denitrification tank, a short-cut nitrification tank, an anaerobic ammonia oxidation tank, a Fenton oxidation tank and a sulfur autotrophic denitrification tank connected in series; the short-cut nitrification tank is connected to the water inlet pipe of the short-cut denitrification tank through a reflux pipe, so as to return the nitrified liquid in the short-cut nitrification tank to the short-cut denitrification tank.

9. The multi-stage multi-phase microbial denitrification device according to claim 8, characterized in that: The upper side walls of the short-range denitrification tank, short-range nitrification tank, anaerobic ammonia oxidation tank and Fenton oxidation tank are all provided with a precipitator for mud-water separation, and the precipitator is provided with a water outlet. Two adjacent biological treatment tanks are connected through the water outlet to realize the series connection of the biological treatment tanks.

10. The multi-stage multi-phase microbial denitrification device according to claim 9, characterized in that: The precipitator comprises a support frame with an internal cavity, wherein the support frame is provided with a water inlet and a water outlet, and the internal cavity of the support frame is provided with a plurality of parallel inclined plates at a position between the water inlet and the water outlet.

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