Sewage treatment device for coupling partial nitrification and denitrification with sulfur autotrophic denitrification

Abstract

The invention discloses a sewage treatment device for coupling partial nitrification and denitrification with sulfur autotrophic denitrification, the sewage treatment device comprises a partial nitrification and denitrification device and an electrochemical sulfur autotrophic denitrification device, the partial nitrification and denitrification device comprises an anoxic tank and an aerobic tank, the anoxic tank is used as a place for carrying out denitrification reaction on landfill leachate, and the aerobic tank is used as a place for carrying out denitrification reaction on the landfill leachate. The aerobic tank is used as a place for carrying out nitration reaction on the landfill leachate; the electrochemical sulfur autotrophic denitrification device comprises an electrochemical sulfur autotrophic denitrification tank, the electrochemical sulfur autotrophic denitrification tank is provided with a filler layer serving as a biological carrier, and an anode and a cathode which are respectively connected with an anode and a cathode of a power supply are arranged in the electrochemical sulfur autotrophic denitrification tank. During operation, the exogenous electric field not only can effectively promote the activity of sulfur autotrophic microorganisms and improve the efficiency of sulfur autotrophic denitrification, but also can promote functional microorganisms to secrete more extracellular polymeric substances so as to tolerate the toxicity of high-concentration nitrite generated by a front-end part nitrification device and landfill leachate.

Description

Technical Field

[0001] The invention belongs to the technical field of biological sewage treatment, and in particular relates to a sewage treatment device for partial nitrification and denitrification coupled with sulfur autotrophic denitrification. Background Art

[0003] The leachate from urban landfills has a complex composition and there is no perfect process suitable for treating it. It is one of the most difficult high-ammonia nitrogen organic wastewaters to treat, mainly manifested in high BOD and COD concentrations, high contents of heavy metals, ammonia nitrogen and total phosphorus, etc. High concentrations of ammonia nitrogen will have serious toxic effects on water bodies, organisms, soil, etc. If the leachate is not properly treated, it will go deep into the ground and cause groundwater and soil pollution. The water and soil polluted by the leachate will have a great impact on human health, and the soil polluted by the leachate will be difficult to recover.

[0004] Traditional heterotrophic nitrification and denitrification, partial nitrification and denitrification, and new anaerobic ammonia oxidation processes have bottleneck problems in the denitrification treatment of landfill leachate, such as incomplete denitrification and high nitrate and nitrite nitrogen contents in the effluent. If the heterotrophic denitrification process is continued to be used for deep denitrification, a large amount of organic carbon source needs to be added, which not only increases the operating cost, but also easily causes secondary pollution caused by the carbon source supplement. If partial nitrification and denitrification is used alone, it may lead to high concentrations of nitrite and nitrate nitrogen in the effluent. Sulfur autotrophic denitrification is a new type of sewage deep denitrification process. It does not require the addition of additional carbon sources, has low carbon emissions, and has low operating costs. It is currently the most cutting-edge denitrification treatment process in the world. However, in actual operation, this process has problems such as rapid alkalinity consumption, low treatment load, low electron transfer efficiency, and low denitrification efficiency.

[0005] Chinese invention patent CN115745165A discloses "device and method for strengthening deep denitrification of domestic sewage by coupling nitrification / denitrification with sulfur autotrophic denitrification / anaerobic ammonium oxidation" which can be used for deep denitrification of domestic sewage. However, since the microorganisms are cultivated in sulfur autotrophic and anaerobic ammonium oxidation, the growth rate is slow and the reproduction time is long, which leads to low efficiency of sulfur autotrophic denitrification and anaerobic ammonium oxidation. The low reaction rate will also cause the reactor volume to increase exponentially, increasing the cost; the temperature has a significant effect on the autotrophic reaction of microorganisms, which will further reduce the reaction rate, which is not high. Moreover, compared with ordinary domestic sewage, garbage leachate itself has strong toxicity and complex composition, which will threaten the growth and reproduction of microorganisms. Obviously, the existing device cannot be used for the treatment of garbage leachate.

[0006] Liu Xiaoshuai et al. in "Current Status and Prospects of Sulfur Autotrophic Denitrification Operation Process" and Huo Da in their published dissertation "Research on Anaerobic Ammonia Oxidation Coupling Sulfur Autotrophic Denitrification to Enhance Nitrogen Removal from Waste Incineration Leachate" both adopted the combination of sulfur autotrophic denitrification with other denitrification processes to circumvent the shortcomings of sulfur autotrophic denitrification. However, the stability of other denitrification processes combined with it, such as anaerobic ammonia oxidation process, is poor and is easily affected by external factors such as ambient temperature, pH, and organic pollutant concentration. As a result, the denitrification stability of the combined process composed of sulfur autotrophic denitrification and other denitrification processes cannot be effectively guaranteed. The combination of sulfur autotrophic denitrification and other denitrification processes will also increase the complexity of the process, and more operating parameters need to be controlled to ensure process stability, which directly or indirectly leads to an increase in the operating cost of the sulfur autotrophic denitrification process, and the by-product hydrogen ions of sulfur autotrophic denitrification cannot be utilized. Summary of the invention

[0007] In order to overcome at least one of the problems in the prior art, the present invention provides a sewage treatment device combining partial nitrification and denitrification coupled with electrochemical sulfur autotrophic deep denitrification, which can efficiently denitrify and effectively treat landfill leachate.

[0008] In order to achieve the purpose of the present invention, the present invention provides a sewage treatment device for partial nitrification and denitrification coupled with sulfur autotrophic denitrification, comprising a partial nitrification and denitrification device and an electrochemical sulfur autotrophic denitrification device.

[0009] Some nitrification and denitrification devices include anoxic tanks and aerobic tanks. The anoxic tanks are used as places for the denitrification reaction of the landfill leachate, and the aerobic tanks are used as places for the nitrification reaction of the landfill leachate.

[0010] The electrochemical sulfur autotrophic denitrification device comprises an electrochemical sulfur autotrophic denitrification tank, which is provided with a filler layer as a biological carrier, and an anode and a cathode for connecting to the positive and negative electrodes of a power supply respectively.

[0011] Furthermore, the anoxic pool is provided with an overflow port, a first flow pusher for stirring, and a reflux pump for pumping water from the aerobic pool back to the anoxic pool. Preferably, the first flow pusher is fixed to the bottom of the anoxic pool, and the overflow port is provided at the middle position of the top of the partition between the anoxic pool and the aerobic pool.

[0012] Furthermore, a water inlet pipe is provided on the anoxic pool. Preferably, the water inlet pipe is inserted from the bottom of the side of the anoxic pool.

[0013] Furthermore, the aerobic tank is provided with an air inlet pipe and an air distribution pipe, the air distribution pipes are evenly distributed at the bottom of the aerobic tank, and the air inlet pipe is connected to the air distribution pipe. Preferably, the air inlet pipe enters from the top of the reactor to the bottom and is connected to the air distribution pipe.

[0014] Furthermore, the air distribution pipes and water distribution pipes are provided in multiple groups, which are symmetrically arranged on both sides of the air inlet pipe and the water inlet pipe, each of the air distribution pipes is perpendicular to the air inlet pipe and connected, each of the water distribution pipes is perpendicular to the water inlet pipe and connected, and the air distribution pipes and water distribution pipes are provided with upward holes.

[0015] Furthermore, it also includes a sedimentation tank, which is located between the aerobic tank and the electrochemical sulfur autotrophic denitrification tank.

[0016] Furthermore, the bottom of the sedimentation tank is in an inverted trapezoidal shape, with both sides inclined toward the middle, and a mud discharge pipe is provided in the middle of the bottom.

[0017] Furthermore, a decanter and a second flowmaker for stirring are provided in the aerobic pool, and the water outlet of the decanter is connected to the sedimentation pool. Preferably, the motor of the decanter is fixed on the platform above the aerobic pool, and the second flowmaker is fixed on the bottom of the aerobic pool.

[0018] The flow promoter plays a stirring role, ensuring that the homogenate is in a flowing state and in full contact with the sewage without precipitation.

[0019] Preferably, the first and second flowmakers are fixed at the bottom corners of the anoxic pool and the aerobic pool respectively using steel pipes as brackets, and the ropes fixed by the pulleys on the top of the brackets are connected vertically downward to the flowmakers.

[0020] Furthermore, the sulfur autotrophic denitrification tank is provided with a water inlet pump for pumping water from the sedimentation tank into the sulfur autotrophic denitrification tank.

[0021] Furthermore, the sulfur autotrophic denitrification tank is also provided with a supporting plate, a water inlet pipe, a water distribution pipe and an adjustable DC regulated power supply. The supporting plate is fixed on the inner wall of the sulfur autotrophic denitrification tank, the filler layer is fixed on the supporting plate, the water inlet pipe is vertically connected to the water distribution pipe and is evenly distributed below the supporting plate. The adjustable DC regulated power supply is arranged on the upper platform of the electrochemical sulfur autotrophic denitrification tank, and the positive and negative electrodes of the adjustable DC regulated power supply are respectively connected to the anode and the cathode.

[0022] Furthermore, the filler layer supporting the sulfur-iron composite biological carrier is evenly filled above the supporting plate, and the filling volume is 60-70% of the volume of the electrochemical sulfur autotrophic denitrification tank.

[0023] Furthermore, the filling material of the sulfide-iron composite biological carrier filling layer is granular, and the particle size is 3 to 10 mm.

[0024] Preferably, the supporting plate is a hollow structure, and holes are formed on the supporting plate.

[0025] Furthermore, it also includes a water outlet pool, which is close to the electrochemical sulfur autotrophic denitrification tank and receives the overflow water of the electrochemical sulfur autotrophic denitrification tank. That is, the device includes an anoxic tank, an aerobic tank, a sedimentation tank, an electrochemical sulfur autotrophic denitrification tank, and a water outlet pool from left to right.

[0026] Furthermore, a water outlet pipe is provided on the water outlet pool. Preferably, the water outlet pipe is provided at the bottom of the pool body and communicated with the outside.

[0027] The aforementioned partial nitrification and denitrification coupled electrochemical sulfur autotrophic denitrification sewage treatment device is used to efficiently denitrify sewage. The sewage is introduced into the anoxic tank of the partial nitrification and denitrification device through the water inlet pipe, and is treated by partial nitrification and denitrification, and then deeply treated by electrochemical sulfur autotrophic denitrification, and then flows out through the overflow tank.

[0028] Preferably, the process operating conditions for efficient nitrogen removal are: the sewage is first subjected to partial nitrification and denitrification treatment, and then enters the electrochemical sulfur autotrophic denitrification tank for denitrification treatment to achieve efficient nitrogen removal, and the total nitrogen in the inlet water is 2000-3100 mg / L.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The present invention provides a sewage treatment device that combines partial nitrification and denitrification with electrochemical sulfur autotrophic denitrification. The treatment device combines a partial nitrification and denitrification device with an electrochemical sulfur autotrophic denitrification device to perform partial nitrification and denitrification and electrochemical sulfur autotrophic denitrification treatment on sewage, and can effectively denitrify landfill leachate.

[0031] (2) The filler layer of the sewage treatment device can be filled with sulfur-iron composite biological carriers as microbial carriers. The carriers have a large specific surface area, strong biological affinity, high porosity, and are easy for microorganisms to attach and form biofilms. During operation, the sulfide in the sulfur-iron composite biological carriers undergoes sulfur autotrophic denitrification. The iron ions in the sulfur-iron composite biological carriers can not only promote the growth of functional microorganisms, promote electron transfer in the denitrification process, and enhance the denitrification efficiency; adding electrodes to the filler layer can balance the pH environment of the reaction system, effectively promote the activity of microorganisms, improve the efficiency of sulfur autotrophic denitrification, and resist the toxicity of the landfill leachate itself.

[0032] (3) The present application uses electrochemical methods to enhance sulfur autotrophic denitrification for efficient nitrogen removal, wherein the application of an external electric field can not only effectively maintain the sulfur autotrophic denitrification reaction system in a neutral pH environment, allowing the functional microorganisms to better undergo denitrification reactions in an optimal pH environment; but also the current stimulation can promote the metabolism of denitrification functional microorganisms and secrete more extracellular polymers and proteins (e.g., under the stimulation of an external electric field of 50 mA, the EPS concentration can be increased by 2.8 times), which is beneficial to the formation of a biofilm on the surface of the sulfur autotrophic biological carrier, thereby achieving the effect of deep denitrification of sewage.

[0033] (4) The present application can reduce hydrogen ions to hydrogen on the surface of the negative electrode by electrochemical means, and the hydrogen can further be used as an electron donor for autotrophic denitrification to remove nitrogen and reduce the production of sulfate byproducts, thereby reducing the sulfate emission risk of the sulfur autotrophic denitrification process while having a good denitrification effect.

[0034] (5) Compared with the prior art mentioned in the background technology, the sewage treatment device provided by the present invention saves the anaerobic ammonia oxidation process, simplifies the treatment process, and saves costs.

[0035] (6) The process of the present invention is simple, has high stability, can quickly replenish biological carriers, and can achieve a denitrification efficiency of more than 97% for landfill leachate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A structural diagram of a sewage treatment device for partial nitrification and denitrification coupled with electrochemical sulfur autotrophic denitrification provided in an embodiment of the present invention;

[0037] Figure 2 This is a physical picture of the sulfide-iron composite biological carrier;

[0038] Figure 3 This is a diagram showing the effect of removing total nitrogen from landfill leachate by a sewage treatment device with partial nitrification and denitrification coupled with electrochemical sulfur autotrophic denitrification in an embodiment of the present invention;

[0039] Figure 4 Schematic diagram of the change in concentration and composition of EPS on the surface of the iron-sulfur composite biological carrier when an external electric field is applied in an embodiment of the present invention;

[0040] Figure 5 In the embodiment of the present invention, S 0 , FeS2 and S 0 : Schematic diagram of the relationship between TN concentration and time when FeS2 treats sewage at different mass ratios.

[0041] Figure 1 In the figure, 1-water inlet pipe, 2-first flow pusher, 3-reflux pump, 4-overflow port, 5-air distribution pipe, 6-decanter, 7-air inlet pipe, 8-sludge discharge pipe, 9-water inlet pump, 10-water inlet pipe, 11-water distribution pipe, 12-supporting plate, 13-filling layer, 14-adjustable DC regulated power supply, 15-cathode, 16-anode, 17-overflow trough, 18-water outlet pipe, 19-anoxic tank, 20-aerobic tank, 21-sedimentation tank, 22-electrochemical sulfur autotrophic denitrification tank, 23-water outlet tank. DETAILED DESCRIPTION

[0042] The specific embodiments of the present invention are further described below. It should be noted that the description of these embodiments is only used to help understand the present invention and is not intended to limit the scope of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] The experimental methods in the following examples, unless otherwise specified, all adopt conventional conditions. The experimental materials used in the following examples, unless otherwise specified, can be purchased through conventional markets or other commercial channels.

[0044] Example 1 A sewage treatment device with partial nitrification and denitrification coupled with sulfur autotrophic denitrification

[0045] like Figure 1 As shown, a sewage treatment device with partial nitrification and denitrification coupled with sulfur autotrophic denitrification includes a partial nitrification and denitrification device and an electrochemical sulfur autotrophic denitrification device. The partial nitrification and denitrification device includes an anoxic tank 19 and an aerobic tank 20, and the electrochemical sulfur autotrophic denitrification device includes an electrochemical sulfur autotrophic denitrification tank 22.

[0046] The sewage treatment device is provided with an anoxic tank 19, an aerobic tank 20, a sedimentation tank 21, an electrochemical sulfur autotrophic denitrification tank 22 and an outlet tank 23 in sequence from left to right.

[0047] The anoxic tank 19 is provided with an inlet pipe 1, a first flow producer 2, a reflux pump 3 and an overflow port 4. The inlet pipe 1 is inserted into the anoxic tank 19 from the bottom of the side of the anoxic tank 19; the flow producer 2 is fixed to the bottom of the anoxic tank 19, and the first flow producer 2 plays a stirring role, which can ensure that the homogenized water is in a flowing state and is in full contact with the sewage without precipitation; the reflux pump 3 is used to pump water from the aerobic tank 20 back to the anoxic tank 19; the overflow port 4 is arranged in the middle position of the top of the partition between the anoxic tank 19 and the aerobic tank 20.

[0048] The first flowmaker 2 is fixed to the bottom of the anoxic pool 19 through a bracket made of a steel pipe. Specifically, the bracket is fixed to the anoxic pool 19, a pulley is provided on the top of the bracket, and the pulley is connected to the first flowmaker 2 through a vertically downward rope.

[0049] The aerobic tank 20 is provided with a second flow producer, an air distribution pipe 5, a decanter 6, and an air inlet pipe 7. The air inlet pipe 7 extends from the top of the sewage treatment device to the bottom and is connected to the air distribution pipe 5. The air distribution pipe 5 is evenly distributed at the bottom of the aerobic tank 20. The second flow producer is fixed to the bottom of the aerobic tank 20. The decanter 6 is located in the aerobic tank 20 and its water outlet is connected to the sedimentation tank 21. The motor of the decanter 6 is fixed to the platform above the aerobic tank 20. The sedimentation tank 21 plays a secondary sedimentation role.

[0050] The second flowmaker is fixed to the bottom of the aerobic tank 20 through a bracket made of a steel pipe. Specifically, the bracket is fixed to the aerobic tank 20, a pulley is provided on the top of the bracket, and the pulley is connected to the second flowmaker through a vertically downward rope.

[0051] The sedimentation tank 21 is provided with a mud discharge pipe 8 . The bottom of the sedimentation tank 21 is in an inverted trapezoidal shape, with both sides inclined toward the middle. The mud discharge pipe 8 is provided in the middle position of the bottom.

[0052] The electrochemical sulfur autotrophic denitrification tank 22 is provided with a water inlet pump 9, a water inlet pipe 10, a water distribution pipe 11, a supporting plate 12, a packing layer 13, an adjustable DC voltage-stabilized power supply 14, a cathode 15 (which can be made of a copper sheet), an anode 16 (which can be made of a titanium sheet), and an overflow tank 17. The water inlet pump 9 is used to pump water from the sedimentation tank 21 into the sulfur autotrophic denitrification tank 22. The water inlet pipe 10 is vertically connected to the water distribution pipe 11, and the water distribution pipe 11 is evenly distributed below the supporting plate 12. The vertical connection can facilitate the uniform arrangement of the water distribution pipes to make the water intake uniform; the supporting plate 12 is fixed on the inner wall of the sulfur autotrophic denitrification tank 22, and the packing layer 13 is fixed in the electrochemical sulfur autotrophic denitrification tank 22 through the supporting plate 12, and the sulfur-iron composite biological carrier is evenly filled as a microbial carrier. The supporting plate 12 plays the role of bearing the packing layer, and the positive and negative electrodes of the adjustable DC voltage-stabilized power supply 14 are respectively connected to the titanium sheet and the copper sheet. The copper sheet is connected to the power supply as a cathode material; the titanium sheet is connected to the power supply as an anode material. The filler layer 13 uses a sulfur-iron composite biological carrier as the main microbial carrier and a sulfur-iron composite biological carrier as a filling material. The filling material is not only conductive, but can also be used as a denitrification electron donor. Under the electrochemical action, the denitrification functional bacteria can be enriched, and the microorganisms can secrete more protein metabolites to achieve the purpose of efficient denitrification. Among them, please refer to Figure 4When the current intensity of the external electric field increased from 0mA to 50mA, the EPS concentration showed a significant increase trend, from 22.0±0.1mg / g·VSS to 64.1±1.1mg / g·VSS when the current intensity increased from 0mA to 40mA. Although the EPS content of the biofilm decreased slightly to 61.4±0.6mg / g·VSS as the current intensity was further increased to 50mA, the EPS concentration still increased by 2.8 times compared with 0mA. A higher EPS concentration is not only conducive to the formation and stabilization of the biofilm on the surface of the filler, but also effectively prevents the functional microorganisms in the biofilm from being affected by inhibitory substances in the landfill leachate, thereby ensuring good denitrification performance. And with the increase of the current intensity of the external electric field, the proportion of PN in EPS also showed a significant increasing trend. Under the conditions of 0, 10, 20, 30, 40 and 50 mA current intensities, the proportion of PN in EPS was 83.0%, 90.3%, 91.1%, 91.5%, 92.5% and 92.1%, respectively. At the same time, with the increase of the proportion of PN in the EPS of the ESAD reactor biofilm, the PN / PS ratio showed a significant upward trend as the current intensity increased from 0mA to 50mA, and reached a peak of 12.4 at 40mA. The above results show that microorganisms can secrete more extracellular proteins under current stimulation, which can help to better form biofilms on the surface of ESAD bioreactor fillers, thereby improving the denitrification efficiency.

[0053] The material ratio of the sulfur-iron composite biological carrier is as follows: sulfur S 0 22.5~67.5%, ferrous disulfide FeS267.5~22.5%, calcium carbonate CaCO3 5%, calcium hydroxide Ca(OH)2 5%. Compared with the prior art, the present invention increases the mass ratio of FeS2 (in the prior art, the FeS2 ratio is 67.5%), and the introduction of sulfur into the sulfide-iron composite biological carrier will, on the one hand, promote the secretion of extracellular polymers and increase the content of extracellular proteins, which is beneficial for microorganisms to form biofilms on the surface of the filler. On the other hand, the positively charged iron ions released by FeS2 are adsorbed in large quantities by the negatively charged EPS, and the iron ions can effectively promote the stability and synthesis of sulfiron protein and Cyt-C in EPS, thereby enhancing the electron transfer ability of EPS, and finally achieving S 0 The composite biological filler with a mass ratio of 1:3 for FeS2 has the best denitrification efficiency for landfill leachate after PN deep nitrification pretreatment. The best treatment effect can be achieved when the proportion of ferrous disulfide FeS2 is in the range of 70-50%. In the prior art, when the proportion of FeS2 is 67.5%, the denitrification effect that can be achieved is 63.7%; pure S 0The denitrification efficiency is 51.2%. The present invention can further improve the denitrification efficiency by about 10-40% by adding and increasing the mass ratio of FeS2 in the sulfide-iron composite biological carrier. However, FeS2 itself does not have a good denitrification effect, and the denitrification efficiency is less than 10%. Therefore, the sulfide-iron composite biological carrier of the present application can greatly improve the denitrification capacity.

[0054] Wherein, the supporting plate 12 is a hollow structure.

[0055] The outlet pool 23 is provided with an outlet pipe 18, which is arranged at the bottom of the pool body and communicates with the outside. The outlet pool 23 serves as a storage pool for the final outlet water.

[0056] When the above-mentioned sewage treatment device is used for denitrification, the sewage enters the anoxic tank 19 from the water inlet pipe 1 at the bottom, overflows into the aerobic tank 20 through the overflow port 4 on the top partition, and is discharged into the sedimentation tank 21 by the decanter 6 after the reaction. Then, it is extracted from the sedimentation tank 21 by the water inlet pump 9, enters the electrochemical sulfur autotrophic denitrification tank 22 in an upflow manner, and flows into the outlet tank through the overflow trough 17 after being treated by the sulfur-iron composite biological carrier filler layer. The filler layer 13 is filled with sulfur-iron composite biological carriers as microbial carriers. The carrier has a large specific surface area, strong biological affinity, high porosity, and is easy for microorganisms to attach. During operation, sulfide in the sulfur-iron composite biological carrier can be used as a denitrification electron donor, and iron ions can be used as an exogenous electron medium to enhance sulfur autotrophic denitrification; adding electrodes to the sulfur-iron composite biological carrier filler layer can effectively promote the activity of microorganisms, improve the efficiency of sulfur autotrophic denitrification, and resist the toxicity of the garbage leachate itself. The present invention has a simple process, high stability, and can quickly replenish biological carriers.

[0057] The partial nitrification and denitrification device provided in this embodiment adopts the method of anoxic first and then aerobic. The sewage enters the anoxic tank from the bottom water inlet pipe, overflows into the aerobic tank through the overflow port, and is discharged into the sedimentation tank by the decanter after the reaction. It is then extracted from the sedimentation tank by a water pump and enters the electrochemical sulfur autotrophic denitrification tank in an upflow manner. After being treated by the sulfur-iron composite biological carrier filler layer, it flows into the outlet tank through the overflow trough. Titanium is used as the anode and copper as the cathode; the sulfur-iron composite biological carrier is used as the microbial carrier. During operation, the external electric field can not only effectively promote the activity of sulfur autotrophic microorganisms and improve the efficiency of sulfur autotrophic denitrification, but also promote the functional microorganisms in the sulfur autotrophic denitrification device to tolerate the high concentration of nitrite produced by the front-end partial nitrification and denitrification device and the toxicity of the garbage leachate itself; and the iron ions in the sulfur-iron composite biological carrier can also enhance the autotrophic denitrification effect of the sulfur autotrophic denitrification device. The present invention has a simple process, high stability, and can quickly replenish biological carriers, and the denitrification efficiency of low carbon-nitrogen ratio garbage leachate reaches more than 97%.

[0058] Example 2 Wastewater treatment method with partial nitrification and denitrification coupled with electrochemical sulfur autotrophic denitrification

[0059] A method for treating sewage by partial nitrification and denitrification coupled with electrochemical sulfur autotrophic denitrification, comprising the following steps:

[0060] The garbage leachate enters the anoxic tank 19 of the sewage treatment device through the water inlet pipe 1, and denitrification reaction is carried out in the anoxic tank 19. The flow pusher 2 stirs to make the homogenate fully contact and react with the sewage, and will not be deposited at the bottom of the tank, and the water in the anoxic tank 19 naturally overflows to the aerobic tank 20; nitrification reaction is carried out in the aerobic tank 20, the air inlet pipe 7 is connected to the blower to aerate the aerobic tank 20, the air distribution pipe 5 makes the aeration uniform, the reflux pump 3 returns the water of the aerobic tank 20 to the anoxic tank 19, and the decanter 6 discharges the supernatant of the aerobic tank 20 to the sedimentation tank 20. pool 21; the sludge after secondary sedimentation in the sedimentation tank 21 is discharged from the bottom through the sludge discharge pipe 8; the water inlet pipe 10 is connected to the water inlet pump 9, and the water inlet pump 9 pumps the supernatant in the sedimentation tank 21 into the electrochemical sulfur autotrophic denitrification tank 22, and the electrochemical sulfur autotrophic denitrification tank 22 performs a denitrification reaction. The water distribution pipe 11 allows the inlet water to enter evenly from the bottom and flow upward, and the overflow tank 17 allows the effluent of the electrochemical sulfur autotrophic denitrification tank 22 to naturally enter the effluent pool 23 in an overflow manner; the treated water is finally discharged from the effluent pool 23 through the effluent pipe 18.

[0061] Example 3 Application effect of a sewage treatment device with partial nitrification and denitrification coupled with electrochemical sulfur autotrophic denitrification.

[0062] The sewage treatment device of partial nitrification and denitrification coupled with electrochemical sulfur autotrophic denitrification in Example 1 was applied to the efficient denitrification treatment of landfill leachate. The process conditions were: the landfill leachate from a landfill was used as the sewage source for treatment, the total nitrogen TN concentration of the landfill leachate was 2000-3100 mg / L, and the treatment capacity was 1.5 m 3 / day, the water inlet mode of the raw solution is intermittent, and the water inlet mode of the electrochemical sulfur autotrophic denitrification device is continuous.

[0063] Denitrification effect Figure 3 As shown, after the sewage treatment device is stably operated, the total nitrogen removal rate reaches more than 97%, the effluent TN is lower than 60.0 mg / L, and the effluent pH can be stably maintained at 8.5±0.4.

[0064] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the protection scope of the present invention.

Claims

1. A sewage treatment device for partial nitrification and denitrification coupled with sulfur autotrophic denitrification, characterized in that: Including partial nitrification and denitrification device and electrochemical sulfur autotrophic denitrification device, Some nitrification and denitrification devices include anoxic tanks and aerobic tanks. The anoxic tanks are used as places for the denitrification reaction of the landfill leachate, and the aerobic tanks are used as places for the nitrification reaction of the landfill leachate. The electrochemical sulfur autotrophic denitrification device comprises an electrochemical sulfur autotrophic denitrification tank, which is provided with a filler layer as a biological carrier, and an anode and a cathode for connecting to the positive and negative electrodes of a power supply respectively.

2. A sewage treatment device for partial nitrification and denitrification coupled with sulfur autotrophic denitrification according to claim 1, characterized in that: The anoxic pool is provided with an overflow port, a first flow pusher for stirring, and a reflux pump for pumping water from the aerobic pool back to the anoxic pool.

3. The sewage treatment device of partial nitrification and denitrification coupled with sulfur autotrophic denitrification according to claim 1, characterized in that: The anoxic pool is provided with a water inlet pipe.

4. The sewage treatment device of partial nitrification and denitrification coupled with sulfur autotrophic denitrification according to claim 1, characterized in that: An air inlet pipe and an air distribution pipe are arranged in the aerobic pool. The air distribution pipes are evenly distributed at the bottom of the aerobic pool. The air inlet pipe is connected to the air distribution pipe.

5. The sewage treatment device of partial nitrification and denitrification coupled with sulfur autotrophic denitrification according to claim 1, characterized in that: The air distribution pipes are arranged in a plurality of groups, and each of the air distribution pipes is perpendicular to the air inlet pipe and is in communication with the air inlet pipe.

6. The sewage treatment device of partial nitrification and denitrification coupled with sulfur autotrophic denitrification according to claim 1, characterized in that: The system also comprises a sedimentation tank, which is located between the aerobic tank and the electrochemical sulfur autotrophic denitrification tank.

7. A sewage treatment device for partial nitrification and denitrification coupled with sulfur autotrophic denitrification according to claim 6, characterized in that: The bottom of the sedimentation tank is in an inverted trapezoidal shape, with both sides inclined toward the middle, and a mud discharge pipe is arranged in the middle position of the bottom.

8. The sewage treatment device of partial nitrification and denitrification coupled with sulfur autotrophic denitrification according to claim 6, characterized in that: A decanter and a second flow pusher for stirring are arranged in the aerobic pool, and the water outlet of the decanter is connected with the sedimentation pool.

9. The sewage treatment device of partial nitrification and denitrification coupled with sulfur autotrophic denitrification according to claim 6, characterized in that: The sulfur autotrophic denitrification tank is provided with a water inlet pump for pumping water from the sedimentation tank into the sulfur autotrophic denitrification tank.

10. A sewage treatment device for partial nitrification and denitrification coupled with sulfur autotrophic denitrification according to any one of claims 1 to 9, characterized in that: The utility model also comprises a water outlet pool, which is close to the electrochemical sulfur autotrophic denitrification pool and receives the overflow water of the electrochemical sulfur autotrophic denitrification pool.

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