A short-range denitrification device and method driven by in-situ re-fermentation of sludge fermentation liquid

Abstract

The present invention discloses a sludge fermentation liquid in-situ re-fermentation driven short-range denitrification device and method, the device includes a fermentation-coupled short-range denitrification reactor and a denitrification synchronous anaerobic ammonium oxidation reactor; the fermentation-coupled short-range denitrification reactor and the denitrification synchronous anaerobic ammonium oxidation reactor are connected through an intermediate water tank. The present invention adopts the above-mentioned sludge fermentation liquid in-situ re-fermentation driven short-range denitrification device and method, further hydrolyzes and acidifies the organic matter in the sludge fermentation liquid to improve the utilization value of the fermentation liquid, realizes the full utilization of the residual sludge carbon source, and simultaneously treats nitrate wastewater and urban sewage through two-stage short-range denitrification / anaerobic ammonium oxidation, which is suitable for deep denitrification and resource utilization of sewage, and is of great significance to the realization of sustainable sewage treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of waste sludge resource utilization and sewage biological denitrification, and specifically relates to a sludge fermentation liquid in-situ re-fermentation driven short-range denitrification device and method. Background Art

[0002] Conventional activated sludge denitrification is still the mainstream in wastewater treatment plants. However, its effective application in treating low carbon-nitrogen ratio wastewater depends largely on the addition of organic matter. Therefore, there is an urgent need to explore alternative carbon sources and autotrophic processes to improve system management innovations and increase the cost-effectiveness and productivity of wastewater treatment. Anaerobic ammonium oxidation (anammox), as an autotrophic process, can achieve efficient nitrogen removal without the need for aeration and organic carbon sources. Compared with traditional nitrogen removal methods, it provides a minimal carbon footprint and reduces sludge production by converting nitrogen into environmentally friendly gases, which enhances its attractiveness in wastewater treatment practices. As a substrate for anammox, ammonia nitrogen can be obtained directly from raw water, while nitrite, as an intermediate of nitrogen compounds, is usually produced through partial nitrification (PN) or partial denitrification (PD). PD can generate nitrite through nitrate reduction, and due to its stable performance and the lack of need for complex regulation strategies, it is becoming a key area of ​​research and is expected to promote the application of anammox in mainstream wastewater treatment.

[0003] Sludge fermentation liquid (SFL), as a complex organic carbon source, is produced by residual sludge fermentation technology. It contains both easily biodegradable components (volatile fatty acids, VFAs) and slowly biodegradable components (such as proteins (PN) and polysaccharides (PS)), and shows great potential in the short-range denitrification process. However, most previous studies have focused on the direct utilization of VFAs, while ignoring the degradable macromolecular organic matter therein, which may bring challenges to the removal of other organic matter in subsequent processes and lead to waste of resources.

[0004] Microorganisms can convert complex organic matter into VFAs under anaerobic conditions, providing a potential source of electron donors for PD. Therefore, it is considered to re-ferment the fermentation broth so that the macromolecular organic matter therein can continue to be converted into VFAs, and continue to be used in the PD process to improve resource utilization. At the same time, UASB with a longer hydraulic retention time can further utilize the complex organic matter in the fermentation broth for denitrification, thereby achieving the effect of deep denitrification. Therefore, the art needs to develop a short-range denitrification device and method driven by in-situ re-fermentation of sludge fermentation broth, which can effectively solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a sludge fermentation liquid in-situ re-fermentation driven short-term denitrification device and method, further hydrolyze and acidify the organic matter in the sludge fermentation liquid to improve the utilization value of the fermentation liquid, realize the full utilization of the residual sludge carbon source, and simultaneously treat nitrate wastewater and urban sewage through two-stage short-term denitrification / anaerobic ammonia oxidation. It is suitable for deep denitrification and resource utilization of sewage, and is of great significance to the realization of sustainable sewage treatment.

[0006] To achieve the above-mentioned purpose, the present invention provides a sludge fermentation liquid in-situ re-fermentation driven short-term denitrification device, comprising a fermentation-coupled short-term denitrification reactor and a denitrification synchronous anaerobic ammonium oxidation reactor; the fermentation-coupled short-term denitrification reactor and the denitrification synchronous anaerobic ammonium oxidation reactor are connected through an intermediate water tank.

[0007] Preferably, a first water inlet is provided on one side of the fermentation-coupled short-range denitrification reactor, a nitrate wastewater inlet tank is provided on the side of the fermentation-coupled short-range denitrification reactor close to the first water inlet, and a first water outlet of the nitrate wastewater inlet tank is connected to the first water inlet through a first water inlet pump.

[0008] Preferably, a second water inlet is provided at the upper end of the fermentation-coupled short-range denitrification reactor away from the first water inlet, and a fermentation liquid inlet tank is provided on the side of the fermentation-coupled short-range denitrification reactor close to the second water inlet, and the fermentation liquid inlet tank is connected to the second water inlet via an inlet pump.

[0009] Preferably, a drain outlet is provided at the lower end of the fermentation-coupled short-range denitrification reactor away from the first water inlet, and an intermediate water tank is provided on the side of the fermentation-coupled short-range denitrification reactor close to the drain outlet; a third water inlet and a second water outlet are respectively provided on both sides of the intermediate water tank; a drain valve is provided between the drain outlet and the third water inlet.

[0010] Preferably, the interior of the fermentation-coupled short-range denitrification reactor is a double-layer structure, the outer layer of which is a water bath area, and a plurality of heating rods are arranged in the water bath area; the top of the inner layer of the fermentation-coupled short-range denitrification reactor is provided with a stirrer and a pH monitor.

[0011] Preferably, a fifth water inlet is provided at the bottom end of the denitrification simultaneous anaerobic ammonium oxidation reactor, and the fifth water inlet is connected to the second water outlet of the intermediate water tank and the fourth water inlet of the urban sewage tank through the second water inlet pump and the third water inlet pump respectively.

[0012] Preferably, the denitrification synchronous anaerobic ammonium oxidation reactor is provided with a reflux outlet, a sixth water inlet, and a U-shaped pipe mouth, and a reflux pump is provided between the reflux outlet and the sixth water inlet;

[0013] A heating device is arranged inside the denitrification synchronous anaerobic ammonium oxidation reactor.

[0014] A method for driving short-range denitrification by in-situ re-fermentation of sludge fermentation liquid, comprising the following steps:

[0015] Step S1, starting and stable operation of a fermentation-coupled short-range denitrification reactor;

[0016] Step S11, the inoculated sludge comes from the short-cut denitrification sludge and the hydrolyzed acidified sludge in the sludge fermentation reactor that have been operated in the laboratory for more than one year, and the two sludges are inoculated at a volume ratio of 2:1. After inoculation, the sludge concentration of the fermentation-coupled short-cut denitrification reactor is 3500-4000 mg VSS / L;

[0017] Step S12, the fermentation-coupled short-cut denitrification reactor is operated in an anaerobic / anoxic mode for three cycles per day;

[0018] The anaerobic stage includes adding fermentation liquid for 1 minute, anaerobic stirring for 4-6 hours, adding water for 4 minutes, anoxic stirring for 1-3 hours, settling for 30 minutes, draining for 5 minutes, and idling for 20 minutes. The drainage ratio of the fermentation-coupled short-range denitrification reactor is 60%;

[0019] Step S12, the fermentation-coupled short-range denitrification reactor is heated in a water bath by a heating rod in the anaerobic stage, the water bath heating temperature is 30-35° C., and the heating is stopped in the anoxic stage;

[0020] In the anaerobic stage, the sludge fermentation liquid in the fermentation liquid inlet tank is pumped into the second water inlet through the inlet pump 40~60mL, COD=10000~12000mg / L, and in the anoxic stage, the nitrate wastewater in the nitrate wastewater inlet tank is used as the inlet water, including NO3 - -N concentration is 40-50 mg / L;

[0021] The pH value of the whole process is not controlled artificially. - -N is converted to NO2 - When the conversion rate of -N is higher than 80% and the reactor runs stably for more than one week, the fermentation-coupled short-range denitrification reactor is successfully started;

[0022] Step S2, starting and stabilizing the denitrification synchronous anaerobic ammonium oxidation reactor;

[0023] Step S3: After the fermentation-coupled short-range denitrification reactor and the denitrification synchronous anaerobic ammonium oxidation reactor are started up respectively, the two are connected in series.

[0024] Preferably, step S2 specifically comprises:

[0025] Step S21, the inoculated sludge is the anaerobic ammonium oxidation granular sludge cultured in the laboratory and the residual sludge from the secondary sedimentation tank of the AAO process of the actual sewage treatment plant, the volume ratio of the two sludges is 2:1, and the sludge concentration after inoculation is 500-6000 mg VSS / L;

[0026] Step S22, sludge acclimation, using nitrite water and actual urban sewage as influent, the NH4 + -N concentration is 40-60mg / L, and nitrite concentration in water is 50mg / L;

[0027] At the same time, in order to maintain the denitrification activity in the denitrification simultaneous anaerobic ammonium oxidation reactor and degrade the COD in urban sewage, 10 mg / L NO3 was added to the nitrite distribution bucket. - -N; adjust the flow rates of the second water inlet pump and the third water inlet pump so that the water flow rates of the two water inlets are 1:1, and the ratio of ammonia nitrogen to nitrite nitrogen is 1:1.3~1:1.4;

[0028] Step S23, the hydraulic retention time is 8-12 hours, the reflux ratio is 300-400%, and the operating temperature is 28-30°C by a heating device;

[0029] Step S24: When the total inorganic nitrogen in the effluent is less than 5 mg / L and is maintained for more than 10 days, the denitrification simultaneous anaerobic ammonium oxidation reactor is successfully started.

[0030] Preferably, step S3 specifically comprises:

[0031] Step S31, adding the sludge fermentation liquid to the fermentation-coupled short-cut denitrification reactor in the anaerobic stage, controlling the temperature to 30-35°C, and performing a hydrolysis and fermentation reaction, after which nitrate wastewater is introduced into the anoxic stage, and the sludge concentration is maintained at 3500-4000 mgVSS / L, and performing a short-cut denitrification reaction;

[0032] Step S32, by measuring NO3 - -N is converted to NO2 - When the conversion rate of -N is above 80%, it is considered that the end point of short-range denitrification has been reached and the precipitation stage has begun;

[0033] a. After the mud and water are separated, the drain valve opens and the supernatant is discharged into the intermediate water tank;

[0034] b. The water in the intermediate water tank is pumped into the denitrification synchronous anaerobic ammonium oxidation reactor through the second water inlet pump. At the same time, actual urban sewage is also pumped in. The flow rates of the second water inlet pump and the third water inlet pump are adjusted so that the flow rates of the two water streams are 1:1, and the ratio of ammonia nitrogen to nitrite nitrogen is 1:1.3~1:1.4;

[0035] c. The reactions carried out in the denitrification synchronous anaerobic ammonium oxidation reactor are anaerobic ammonium oxidation and denitrification, the hydraulic retention time is 8-12h, the reflux ratio is 300~400%, and the operating temperature is 28~30℃;

[0036] d. Ammonia nitrogen and nitrate nitrogen are removed simultaneously, and the final effluent is discharged through the U-shaped pipe outlet.

[0037] The present invention adopts the above-mentioned sludge fermentation liquid in-situ re-fermentation driven short-range denitrification device and method, and the beneficial effects are as follows:

[0038] (1) A two-stage short-cut denitrification anaerobic ammonium oxidation process was constructed, which achieved the simultaneous treatment of nitrate wastewater and urban sewage by a combined short-cut denitrification anaerobic ammonium oxidation process, broadening the applicability of anaerobic ammonium oxidation in treating actual sewage;

[0039] (2) This two-stage process does not require aeration, saving 100% of aeration energy consumption. The sludge fermentation liquid is used for re-fermentation to increase the content of VFAs. The advantage of short-range denitrification in saving carbon sources is further expanded. It does not require complex startup and operation strategies, and can maintain long-term stable operation of the system.

[0040] (3) Using sludge fermentation liquid as a carbon source to drive short-range denitrification can reduce the cost of carbon sources while achieving the reduction and resource utilization of excess sludge;

[0041] (4) The two-stage short-range denitrification anaerobic ammonium oxidation process can ensure the stable operation of two separate systems. The inoculation of anaerobic ammonium oxidation granular sludge reduces the impact of organic matter on anaerobic ammonium oxidation. The system is highly controllable and robust.

[0042] (5) After being degraded in the fermentation-coupled short-range denitrification reactor, the complex organic matter in the sludge fermentation liquid can be further degraded and utilized in the denitrification simultaneous anaerobic ammonium oxidation reactor, which is helpful to solve the problem of high effluent COD caused by the addition of fermentation liquid.

[0043] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the overall structure of an embodiment of a sludge fermentation liquid in-situ re-fermentation driven short-range denitrification device and method of the present invention.

[0045] Reference numerals

[0046] 1. Nitrate wastewater inlet tank; 101. First water outlet; 102. First water inlet pump;

[0047] 2. Fermentation coupled short-range denitrification reactor; 201. First water inlet; 202. pH monitor; 203. Agitator; 204. Second water inlet; 205. Drain; 206. Drain valve; 207. Heating rod; 208. Water bath area;

[0048] 3. Fermentation liquid inlet tank; 301. Liquid inlet pump;

[0049] 4. Intermediate water tank; 401. Third water inlet; 402. Second water outlet; 403. Second water inlet pump;

[0050] 5. Urban sewage tank; 501. Fourth water inlet; 502. Third water inlet pump;

[0051] 6. Denitrification simultaneous anaerobic ammonium oxidation reactor; 601. fifth water inlet; 602. heating device; 603. reflux outlet; 604. reflux pump; 605. sixth water inlet; 606. U-shaped pipe mouth. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0053] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0054] like Figure 1 As shown, a denitrification device for simultaneously treating nitrate wastewater and urban sewage by in-situ re-fermentation of organic matter in sludge fermentation liquid to drive a short-cut denitrification / anaerobic ammonium oxidation process comprises a fermentation-coupled short-cut denitrification reactor 2 and a denitrification synchronous anaerobic ammonium oxidation reactor 6. The fermentation-coupled short-cut denitrification reactor 2 and the denitrification synchronous anaerobic ammonium oxidation reactor 6 are connected via an intermediate water tank 4.

[0055] A first water inlet 201 is provided on one side of the fermentation-coupled short-range denitrification reactor 2, and a nitrate wastewater inlet tank 1 is provided on the side of the fermentation-coupled short-range denitrification reactor 2 close to the first water inlet 201. The first water outlet 101 of the nitrate wastewater inlet tank 1 is connected to the first water inlet 201 through a first water inlet pump 102.

[0056] A second water inlet 204 is provided at the upper end of the fermentation-coupled short-range denitrification reactor 2 away from the first water inlet 201 , and a fermentation liquid inlet tank 3 is provided on the side of the fermentation-coupled short-range denitrification reactor 2 close to the second water inlet 204 . The fermentation liquid inlet tank 3 is connected to the second water inlet 204 via an inlet pump 301 .

[0057] A drain port 205 is provided at the lower end of the fermentation-coupled short-cut denitrification reactor 2 on the side away from the first water inlet 201, and an intermediate water tank 4 is provided on the side of the fermentation-coupled short-cut denitrification reactor 2 close to the drain port 205. A third water inlet 401 and a second water outlet 402 are provided on both sides of the intermediate water tank 4. A drain valve 206 is provided between the drain port 205 and the third water inlet 401, and the effluent of the fermentation-coupled short-cut denitrification reactor 2 is discharged into the intermediate water tank 4.

[0058] The fermentation coupled short-range denitrification reactor 2 has a double-layer structure, the outer layer of which is a water bath area 208, and a plurality of heating rods 207 are arranged in the water bath area 208. A stirrer 203 and a pH monitor 202 are arranged at the top of the inner layer of the fermentation coupled short-range denitrification reactor 2.

[0059] A fifth water inlet 601 is provided at the bottom of the denitrification synchronous anaerobic ammonium oxidation reactor 6, and the fifth water inlet 601 is connected to the second water outlet 402 of the intermediate water tank 4 and the fourth water inlet 501 of the urban sewage tank 5 through the second water inlet pump 403 and the third water inlet pump 502 respectively. A reflux outlet 603, a sixth water inlet 605, and a U-shaped nozzle 606 are provided on the denitrification synchronous anaerobic ammonium oxidation reactor 6, and a reflux pump 604 is provided between the reflux outlet 603 and the sixth water inlet 605. The reflux water flows through the reflux outlet 603 through the reflux pump 604 and flows back to the sixth water inlet 605, and the effluent of the denitrification synchronous anaerobic ammonium oxidation reactor 6 is discharged through the U-shaped nozzle 606. A heating device 602 is provided inside the denitrification synchronous anaerobic ammonium oxidation reactor 6.

[0060] Example

[0061] A method for driving short-range denitrification by in-situ re-fermentation of sludge fermentation liquid, comprising the following steps:

[0062] Step S1, starting and stably operating the fermentation-coupled short-cut denitrification reactor 2.

[0063] Step S11, the inoculated sludge comes from the short-cut denitrification sludge that has been running in the laboratory for more than one year and the hydrolyzed acidified sludge in the sludge fermentation reactor. The two sludges are inoculated at a volume ratio of 2:1. After inoculation, the sludge concentration of the fermentation-coupled short-cut denitrification reactor 2 is 3500-4000 mg VSS / L.

[0064] Step S12, the fermentation-coupled short-cut denitrification reactor 2 is operated in an anaerobic / anoxic mode for three cycles per day.

[0065] The anaerobic stage includes adding fermentation liquid for 1 minute, anaerobic stirring for 6 hours, adding water for 4 minutes, anoxic stirring for 1 hour, sedimentation for 30 minutes, drainage for 5 minutes, and idleness for 20 minutes. The drainage ratio of the fermentation-coupled short-range denitrification reactor 2 is 60%.

[0066] Step S12: The fermentation-coupled short-range denitrification reactor 2 is heated in a water bath by the heating rod 207 during the anaerobic stage. The water bath heating temperature is 30-35° C., and the heating is stopped during the anoxic stage.

[0067] In the anaerobic stage, the sludge fermentation liquid in the fermentation liquid inlet tank 3 is pumped into the second water inlet 204 through the inlet pump 301, with a volume of 40-60 mL and a COD of 10,000-12,000 mg / L. In the anoxic stage, the nitrate wastewater in the nitrate wastewater inlet tank 1 is used as the inlet water, wherein NO3 - The concentration of -N is 40 mg / L.

[0068] The pH value of the whole process is not controlled artificially. - -N is converted to NO2 - When the conversion rate of -N is higher than 80% and the reactor operates stably for more than one week, the fermentation-coupled short-range denitrification reactor 2 is successfully started.

[0069] Through the hydrolysis and acidification in the anaerobic stage, the complex organic matter in the fermentation liquid is hydrolyzed and fermented again to convert into volatile fatty acids VFAs, thereby increasing the content of VFAs to reduce the amount of fermentation liquid. In the anoxic stage, microorganisms use VFAs as carbon source to carry out short-range denitrification to convert nitrate nitrogen into nitrite nitrogen, and the effluent flows into the intermediate water tank 4.

[0070] Step S2: starting and stably operating the denitrification synchronous anaerobic ammonium oxidation reactor 6.

[0071] Step S21, the inoculated sludge is the anaerobic ammonium oxidation granular sludge cultured in the laboratory and the residual sludge from the secondary sedimentation tank of the AAO process of the actual sewage treatment plant. The volume ratio of the two sludges is 2:1, and the sludge concentration after inoculation is 500-6000 mg VSS / L.

[0072] Step S22, sludge acclimation, using nitrite water and actual urban sewage as influent, the NH4 + -N concentration is 40-60mg / L, and the concentration of nitrite in water is 50mg / L.

[0073] At the same time, in order to maintain the denitrification activity in the denitrification simultaneous anaerobic ammonium oxidation reactor 6 and degrade the COD in the urban sewage, 10 mg / L NO3 was added to the nitrite distribution tank. - -N. The flow rates of the second water inlet pump 403 and the third water inlet pump 502 are adjusted so that the flow rates of the two inlet waters are 1:1 and the ratio of ammonia nitrogen to nitrite nitrogen is 1:1.3.

[0074] Step S23, the hydraulic retention time is 12 hours, the reflux ratio is 300-400%, and the operating temperature is 28-30°C through the heating device 602.

[0075] Step S24: When the total inorganic nitrogen in the effluent is lower than 5 mg / L and is maintained for more than 10 days, the denitrification synchronous anaerobic ammonium oxidation reactor 6 is successfully started.

[0076] Step S3: After the fermentation-coupled short-cut denitrification reactor 2 and the denitrification synchronous anaerobic ammonium oxidation reactor 6 are started up respectively, the two are connected in series.

[0077] The inlet water of the denitrification synchronous anaerobic ammonium oxidation reactor 6 is the effluent of the fermentation-coupled short-cut denitrification reactor 2 and urban sewage. The ammonia nitrogen in the urban sewage and the nitrite nitrogen in the effluent of the fermentation-coupled short-cut denitrification reactor 2 are converted into nitrogen gas through anaerobic ammonium oxidation reaction. At the same time, the nitrate nitrogen generated is removed by denitrification using organic matter in the effluent and urban sewage.

[0078] Step S31, the sludge fermentation liquid is added to the fermentation-coupled short-cut denitrification reactor 2 in the anaerobic stage, the temperature is controlled at 30-35°C, and the hydrolysis and fermentation reaction is carried out. Thereafter, the nitrate wastewater raw water is introduced into the anoxic section, and the sludge concentration is maintained at 3500-4000 mg VSS / L to carry out the short-cut denitrification reaction.

[0079] Step S32, by measuring NO3 - -N is converted to NO2 - When the conversion rate of -N is above 80%, it is considered that the end point of short-range denitrification has been reached and the precipitation stage has begun.

[0080] a. After the mud and water are separated, the drain valve 206 is opened and the supernatant is discharged into the intermediate water tank 4.

[0081] b. The water in the intermediate water tank 4 is pumped into the denitrification synchronous anaerobic ammonium oxidation reactor 6 through the second water inlet pump 403. At the same time, actual urban sewage is also pumped in. The flow rates of the second water inlet pump 403 and the third water inlet pump 502 are adjusted so that the flow rates of the two water streams are 1:1, and the ratio of ammonia nitrogen to nitrite nitrogen is 1:1.3.

[0082] c. The reactions carried out in the denitrification synchronous anaerobic ammonium oxidation reactor 6 are anaerobic ammonium oxidation and denitrification, with a hydraulic retention time of 8-12 hours, a reflux ratio of 300-400%, and an operating temperature of 28-30°C.

[0083] d. Ammonia nitrogen and nitrate nitrogen are removed simultaneously, and the final effluent is discharged through the U-shaped nozzle 606.

[0084] The wastewater treated in this embodiment has a final effluent ammonia nitrogen concentration of 1.5-5.0 mg / L, a total inorganic nitrogen concentration of 6.4-10.5 mg / L, and a COD concentration of 50-75 mg / L.

[0085] In summary, the two-stage system in this embodiment saves 100% of aeration energy consumption, significantly reduces the addition of external carbon sources, uses sludge fermentation liquid as a carbon source at a low cost, and re-fermentation reduces the amount of fermentation liquid added. It can treat nitrate wastewater and urban sewage at the same time, providing a new idea for energy saving and consumption reduction in actual sewage treatment plants.

[0086] Therefore, the present invention adopts the above-mentioned sludge fermentation liquid in-situ re-fermentation driven short-term denitrification device and method, further hydrolyzes and acidifies the organic matter in the sludge fermentation liquid to improve the utilization value of the fermentation liquid, realizes the full utilization of the residual sludge carbon source, and simultaneously treats nitrate wastewater and urban sewage through two-stage short-term denitrification / anaerobic ammonia oxidation, which is suitable for deep denitrification and resource utilization of sewage, and is of great significance to the realization of sustainable sewage treatment.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A sludge fermentation liquid in-situ re-fermentation driven short-range denitrification device, characterized in that: It comprises a fermentation-coupled short-range denitrification reactor and a denitrification synchronous anaerobic ammonium oxidation reactor; the fermentation-coupled short-range denitrification reactor and the denitrification synchronous anaerobic ammonium oxidation reactor are connected via an intermediate water tank; A first water inlet is provided on one side of the fermentation-coupled short-range denitrification reactor, a nitrate wastewater inlet tank is provided on one side of the fermentation-coupled short-range denitrification reactor close to the first water inlet, and a first water outlet of the nitrate wastewater inlet tank is connected to the first water inlet via a first water inlet pump; The fermentation-coupled short-range denitrification reactor is provided with a second water inlet at the upper end away from the first water inlet, and a fermentation liquid inlet tank is provided on the side of the fermentation-coupled short-range denitrification reactor close to the second water inlet, and the fermentation liquid inlet tank is connected to the second water inlet through an inlet pump; A fifth water inlet is provided at the bottom of the denitrification synchronous anaerobic ammonium oxidation reactor, and the fifth water inlet is connected to the second water outlet of the intermediate water tank and the fourth water inlet of the urban sewage tank through the second water inlet pump and the third water inlet pump respectively.

2. A sludge fermentation liquid in-situ re-fermentation driven short-range denitrification device according to claim 1, characterized in that: A drain outlet is provided at the lower end of the fermentation-coupled short-range denitrification reactor away from the first water inlet, and an intermediate water tank is provided on the side of the fermentation-coupled short-range denitrification reactor close to the drain outlet; a third water inlet and a second water outlet are respectively provided on both sides of the intermediate water tank; a drain valve is provided between the drain outlet and the third water inlet.

3. A sludge fermentation liquid in-situ re-fermentation driven short-range denitrification device according to claim 2, characterized in that: The fermentation-coupled short-range denitrification reactor has a double-layer structure inside, the outer layer of which is a water bath area, and a plurality of heating rods are arranged in the water bath area; a stirrer and a pH monitor are arranged at the top of the inner layer of the fermentation-coupled short-range denitrification reactor.

4. A sludge fermentation liquid in-situ re-fermentation driven short-range denitrification device according to claim 3, characterized in that: The denitrification synchronous anaerobic ammonium oxidation reactor is provided with a reflux outlet, a sixth water inlet, and a U-shaped pipe mouth, and a reflux pump is provided between the reflux outlet and the sixth water inlet; A heating device is arranged inside the denitrification synchronous anaerobic ammonium oxidation reactor.

5. A method for driving short-range denitrification by in-situ re-fermentation of sludge fermentation liquid to drive short-range denitrification device as claimed in claim 4, characterized in that: The following steps are involved: Step S1, starting and stable operation of a fermentation-coupled short-range denitrification reactor; Step S11, the inoculated sludge comes from the short-cut denitrification sludge and the hydrolyzed acidified sludge in the sludge fermentation reactor that have been operated in the laboratory for more than one year, and the two sludges are inoculated at a volume ratio of 2:

1. After inoculation, the sludge concentration of the fermentation-coupled short-cut denitrification reactor is 3500-4000 mg VSS / L; Step S12, the fermentation-coupled short-cut denitrification reactor is operated in an anaerobic / anoxic mode for three cycles per day; The anaerobic stage includes adding fermentation liquid for 1 minute, anaerobic stirring for 4-6 hours, adding water for 4 minutes, anoxic stirring for 1-3 hours, settling for 30 minutes, draining for 5 minutes, and idling for 20 minutes. The drainage ratio of the fermentation-coupled short-range denitrification reactor is 60%; Step S12, the fermentation-coupled short-range denitrification reactor is heated in a water bath by a heating rod in the anaerobic stage, the water bath heating temperature is 30-35° C., and the heating is stopped in the anoxic stage; In the anaerobic stage, the sludge fermentation liquid in the fermentation liquid inlet tank is pumped into the second water inlet through the inlet pump 40~60mL, COD=10000~12000mg / L, and in the anoxic stage, the nitrate wastewater in the nitrate wastewater inlet tank is used as the inlet water, including NO3 - -N concentration is 40-50 mg / L; The pH value of the whole process is not controlled artificially. - -N is converted to NO2 - When the conversion rate of -N is higher than 80% and the reactor runs stably for more than one week, the fermentation-coupled short-range denitrification reactor is successfully started; Step S2, starting and stabilizing the denitrification synchronous anaerobic ammonium oxidation reactor; Step S3: After the fermentation-coupled short-range denitrification reactor and the denitrification synchronous anaerobic ammonium oxidation reactor are started up respectively, the two are connected in series.

6. The method of in-situ re-fermentation of sludge fermentation liquid to drive short-range denitrification according to claim 5, characterized in that: Step S2 specifically includes: Step S21, the inoculated sludge is the anaerobic ammonium oxidation granular sludge cultured in the laboratory and the residual sludge from the secondary sedimentation tank of the AAO process of the actual sewage treatment plant, the volume ratio of the two sludges is 2:1, and the sludge concentration after inoculation is 500-6000 mg VSS / L; Step S22, sludge acclimation, using nitrite water and actual urban sewage as influent, the NH4 + -N concentration is 40-60mg / L, and nitrite concentration in water is 50mg / L; At the same time, in order to maintain the denitrification activity in the denitrification simultaneous anaerobic ammonium oxidation reactor and degrade the COD in urban sewage, 10 mg / L NO3 was added to the nitrite distribution bucket. - -N; adjust the flow rates of the second water inlet pump and the third water inlet pump so that the water flow rates of the two water inlets are 1:1, and the ratio of ammonia nitrogen to nitrite nitrogen is 1:1.3~1:1.4; Step S23, the hydraulic retention time is 8-12 hours, the reflux ratio is 300-400%, and the operating temperature is 28-30°C by a heating device; Step S24: When the total inorganic nitrogen in the effluent is less than 5 mg / L and is maintained for more than 10 days, the denitrification simultaneous anaerobic ammonium oxidation reactor is successfully started.

7. The method of in-situ re-fermentation of sludge fermentation liquid to drive short-range denitrification according to claim 6, characterized in that: Step S3 specifically comprises: Step S31, adding the sludge fermentation liquid to the fermentation-coupled short-cut denitrification reactor in the anaerobic stage, controlling the temperature to 30-35°C, and performing a hydrolysis and fermentation reaction, after which nitrate wastewater is introduced into the anoxic stage, and the sludge concentration is maintained at 3500-4000 mgVSS / L, and performing a short-cut denitrification reaction; Step S32, by measuring NO3 - -N is converted to NO2 - When the conversion rate of -N is above 80%, it is considered that the end point of short-range denitrification has been reached and the precipitation stage has begun; a. After the mud and water are separated, the drain valve is opened and the supernatant is discharged into the intermediate water tank; b. The water in the intermediate water tank is pumped into the denitrification synchronous anaerobic ammonium oxidation reactor through the second water inlet pump. At the same time, actual urban sewage is also pumped in. The flow rates of the second water inlet pump and the third water inlet pump are adjusted so that the flow rates of the two water streams are 1:1, and the ratio of ammonia nitrogen to nitrite nitrogen is 1:1.3~1:1.4; c. The reactions carried out in the denitrification synchronous anaerobic ammonium oxidation reactor are anaerobic ammonium oxidation and denitrification, the hydraulic retention time is 8-12h, the reflux ratio is 300~400%, and the operating temperature is 28~30℃; d. Ammonia nitrogen and nitrate nitrogen are removed simultaneously, and the final effluent is discharged through the U-shaped pipe outlet.

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