A solar energy driven three-dimensional biofilm electrode denitrification device and method

Abstract

The application discloses a kind of three-dimensional biofilm electrode denitrification device and method based on solar drive, including being separated from bottom to top in microbial separator denitrification zone, ammonia nitrogen removal zone and advanced treatment zone, denitrification zone is filled with carbon release filler, ammonia nitrogen removal zone is filled with polyurethane filler, advanced treatment zone is filled with modified polyurethane filler;Microbial separator bottom denitrification zone is communicated with inlet pipe;Denitrification zone and ammonia nitrogen removal zone are provided with water distribution zone between, and water distribution zone is communicated with outlet pipe;Cathode plate and anode plate respectively connected solar panel are inserted in microbial separator;Ammonia nitrogen removal zone is equipped with aeration device;Through in each filler, electrode electrolysis and aeration effect, hydrogen autotrophic denitrification process is carried out to sewage in microbial separator whole process.The present application treats low C / N reservoir water body, to mix culture denitrification combines nitrification, and supplementary aerobic denitrification realizes the efficient removal of nitrogen, with the advantages of high denitrification efficiency, low energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen autotrophic denitrification deep denitrification, and in particular to a solar-driven three-dimensional biofilm electrode denitrification device and method. Background Art

[0002] Water source reservoirs are the main source of water, accounting for more than 45% of the country's water supply; excessive nitrogen, especially the accumulation of nitrates and nitrites, which leads to algal blooms, is the main problem of water source reservoirs. Water source reservoirs are oligotrophic and have low organic matter content. How to achieve denitrification under low C / N conditions is a major problem. Traditional water denitrification technologies, such as biological denitrification and physical and chemical methods, usually rely on high carbon-nitrogen ratio (C / N) conditions. However, many reservoirs and lake water sources have insufficient organic carbon sources and low C / N ratios, making it difficult for traditional denitrification processes to achieve ideal denitrification effects. To meet this challenge, there is an urgent need to develop a green technology that can still efficiently denitrify under low C / N conditions.

[0003] Therefore, how to provide a method for achieving efficient nitrogen removal by combining hydrogen autotrophic denitrification with nitrification under the synergistic effect of aerobic denitrification has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] In order to solve the above-mentioned defects in the prior art, the purpose of the present invention is to provide a three-dimensional biofilm electrode denitrification device and method based on solar energy drive, which can achieve efficient removal of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in sewage, and has the advantages of significant denitrification effect, simple operation and low energy consumption. It is suitable for the field of efficient denitrification technology of low C / N reservoir water bodies.

[0005] The present invention is achieved through the following technical solutions.

[0006] In one aspect, the present invention provides a solar-powered three-dimensional biofilm electrode denitrification device, comprising a microbial separator, which is divided from bottom to top into a denitrification zone, an ammonia nitrogen removal zone, and a deep treatment zone. The denitrification zone is filled with a carbon-releasing filler, the ammonia nitrogen removal zone is filled with a polyurethane filler, and the deep treatment zone is filled with a modified polyurethane filler.

[0007] The denitrification zone at the bottom of the microbial separator is connected to the water inlet pipe; a water distribution zone is set between the denitrification zone and the ammonia nitrogen removal zone, and the water distribution zone is connected to the water outlet pipe;

[0008] A cathode plate and an anode plate connected to the solar panels are inserted into the microbial separator; an ammonia nitrogen removal area is provided with an aeration device;

[0009] The sewage in the microbial separator is subjected to a full process of hydrogen autotrophic denitrification under the action of various fillers, electrode electrolysis and aeration.

[0010] Preferably, the preparation of the polyurethane filler includes: cutting the hydrophilic polyurethane sponge into small pieces, fully soaking and cleaning the polyurethane sponge with pure water, taking it out and drying it to form the polyurethane filler.

[0011] Preferably, the modified polyurethane filler is prepared by cutting a hydrophilic polyurethane sponge into small pieces, then immersing the polyurethane sponge in a mixture of Mn3O4 and aqueous polyurethane in a mass ratio of (1 to 5): (5 to 20), after sufficient immersion, taking out and drying, and then forming a modified polyurethane filler.

[0012] Preferably, the carbon-releasing filler is specifically prepared by:

[0013] 1) Carbonizing corn cob powder at a temperature of 200-300° C.;

[0014] 2) heating and dissolving the polyvinyl alcohol in a water bath at a temperature of 60 to 80° C. in a mass ratio of pure water to polyvinyl alcohol of (3 to 5):1 to obtain a polyvinyl alcohol solution;

[0015] 3) Nano-zero-valent iron and polyvinyl alcohol solution are mixed in a mass ratio of (3-10): (80-100) to obtain a mixed solution, and then carbonized corn cob powder is added to the mixed solution in a mass ratio of polyvinyl alcohol solution: carbonized corn cob = (0.5-1): (3-5), and the mixture is shaped into a spherical carbon-releasing filler while hot. After cooling, the mixture is dried in an oven to obtain the carbon-releasing filler.

[0016] Preferably, a microbial separator is provided in the middle of the water distribution area, the water distribution area is connected to the water outlet pipe through a reflux pipe, and a reflux pressure pump is provided on the reflux pipe.

[0017] Preferably, the cathode plate and the anode plate are platinum-coated titanium electrodes.

[0018] Preferably, the aeration device includes an aeration head connected to the aerator in the ammonia nitrogen removal zone.

[0019] Preferably, a perforated partition is provided between the ammonia nitrogen removal zone and the deep treatment zone; and a pollutant monitoring and alarm device is provided above the deep treatment zone.

[0020] Another aspect of the present invention provides a denitrification method of the solar-driven three-dimensional biofilm electrode denitrification device, comprising:

[0021] (a) a denitrification zone, an ammonia nitrogen removal zone, and an advanced treatment zone are connected in series, a carbon-releasing filler is placed in the denitrification zone, a polyurethane filler is placed in the ammonia nitrogen removal zone, and a modified polyurethane filler is placed in the advanced treatment zone;

[0022] The carbon-releasing filler corncob powder is carbonized at a temperature of 200-300 DEG C, polyvinyl alcohol is dissolved in a water bath by heating and dissolving according to a mass ratio of pure water to polyvinyl alcohol of (3-5):1, the temperature is controlled at 60-80 DEG C, the nano zero-valent iron is mixed with the polyvinyl alcohol solution according to a mass ratio of (3-10):(80-100), the carbonized corncob powder is added into the mixed solution according to a mass ratio of polyvinyl alcohol solution:carbonized corncob of (0.5-1):(3-5), and the carbon-releasing filler in a spherical shape is formed while hot, and is dried in an oven after cooling.

[0023] The modified polyurethane filler is prepared by immersing small pieces of polyurethane sponge into a mixed solution of Mn3O4 and water-based polyurethane according to a mass ratio of (1-5):(5-20), and then drying after sufficient soaking;

[0024] (b) water is fed from a water inlet pipe and discharged from a water outlet pipe, and the ammonia nitrogen concentration, nitrate nitrogen concentration, total nitrogen concentration and COD concentration of the water are controlled;

[0025] (c) the solar panels supply electricity to the cathode plate and the anode plate of the microbial separator for electrolysis, the aeration device aerates the ammonia nitrogen removal zone, and the hydraulic retention time is controlled to carry out the hydrogen autotrophic denitrification process of the whole sewage.

[0026] Preferably, the ammonia nitrogen concentration of the water is 9.00 mg / L-11.50 mg / L, the nitrate nitrogen concentration is 19.50 mg / L-22.00 mg / L, the total nitrogen concentration is 30.00 mg / L-33.50 mg / L, and the COD concentration is 4.50 mg / L-6.00 mg / L;

[0027] The aeration condition is maintained at 2.0-4.0 mg / L;

[0028] The hydraulic retention time is 2-3 hours.

[0029] The present application has the following beneficial effects due to the above technical solutions:

[0030] 1. The sewage is subjected to anaerobic treatment by the carbon-releasing filler in the denitrification zone, and the COD and nitrate nitrogen in the sewage are removed through the action of organic electron donors (corncob) and inorganic electron donors (hydrogen).

[0031] 2. The polyurethane filler filled in the reactor serves as a carrier for the growth of microorganisms in the ammonia nitrogen removal zone, and the efficient removal of nitrate nitrogen is realized through hydrogen autotrophic denitrification, and the nitrification is realized under the action of aeration, thereby realizing the synergistic and efficient removal of ammonia nitrogen and nitrate nitrogen.

[0032] 3. The deep treatment zone modified polyurethane filler further removes ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in the low C / N reservoir water body in a deep and efficient manner, and a pollutant monitoring and alarm system is arranged above the deep treatment zone to monitor the COD and TN in the effluent, and if the effluent does not meet the standard, it is recycled to the water distribution zone for further treatment until the effluent meets the standard, thereby significantly improving the applicability of the reactor.

[0033] 4. The entire reactor realizes hydrogen autotrophic denitrification under the action of the electrode, and in combination with the nitrification and denitrification of each zone, the denitrification performance of the entire reactor is greatly improved.

[0034] The three-dimensional biofilm electrode denitrification device based on solar energy driving can efficiently remove ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in the low C / N reservoir water body, has the advantages of remarkable denitrification effect, simple operation and low energy consumption, and is suitable for the field of efficient denitrification technology of low C / N reservoir water body. BRIEF DESCRIPTION OF DRAWINGS

[0035] The drawings described herein are used to provide a further understanding of the present application, constitute a part of the present application, and do not constitute an improper limitation to the present application, and in the drawings:

[0036] Figure 1 Fig. 1 is a structural schematic view of the three-dimensional biofilm electrode denitrification device based on solar energy driving according to an embodiment of the present application.

[0037] Explanation of reference signs: 1-denitrification zone, 2-ammonia nitrogen removal zone, 3-deep treatment zone, 4-carbon release filler, 5-polyurethane filler, 6-modified polyurethane filler, 7-water distribution zone, 8-microorganism separator, 9-influent pipe, 10-effluent pipe, 11-reflux pipe, 12-reflux pressurizing pump, 13-aerator, 14-aeration head, 15-cathode plate, 16-anode plate, 17-solar panel, 18-pollutant monitoring and alarm device. DETAILED DESCRIPTION

[0038] The present application will be described in detail below in combination with the drawings and specific embodiments, and the schematic embodiments and descriptions of the present application are used to explain the present application, but do not constitute a limitation to the present application.

[0039] As Figure 1As shown, the solar energy driven three-dimensional biofilm electrode denitrification device provided by the present application comprises a microorganism separator 8, which is divided into a denitrification zone 1, an ammonia nitrogen removal zone 2 and a deep treatment zone 3 from bottom to top. The denitrification zone 1 is filled with carbon release fillers 4, the ammonia nitrogen removal zone 2 is filled with polyurethane fillers 5, and the deep treatment zone 3 is filled with modified polyurethane fillers 6. An outflow zone 7 is arranged between the denitrification zone 1 and the ammonia nitrogen removal zone 2, a perforated partition is arranged between the ammonia nitrogen removal zone 2 and the deep treatment zone 3, and an aeration head 14 connected with an aerator 13 is arranged in the ammonia nitrogen removal zone 2. The bottom of the microorganism separator 8 is connected with an inlet pipe 9, the outflow zone 7 is connected with an outlet pipe 10 through a reflux pipe 11, and a reflux pump 12 is arranged on the reflux pipe 11.

[0040] A pollutant monitoring and alarming device 18 is arranged in the deep treatment zone 3. The pollutant monitoring and alarming system is installed above the deep treatment zone 3 to monitor the COD and TN of the treated water. If the water quality does not meet the standard, the effluent is recycled to the outflow zone 7 for treatment again until the effluent meets the standard and is discharged from the outlet pipe 10.

[0041] The microorganism separator 8 is inserted with a cathode plate 15 and an anode plate 16. The cathode plate 15 and the anode plate 16 are platinum-coated titanium electrodes and are connected with solar panels 17 to provide direct current power for the electrode plates.

[0042] The denitrification zone 1 is controlled to be an anaerobic environment to realize the denitrification process. The ammonia nitrogen removal zone 2 realizes the aerobic function through aeration, so that the deep treatment zone 3 is also in an aerobic environment. The outflow zone 7 realizes uniform water distribution for the inlet water and the reflux water. The microorganism separator is arranged in the middle of the outflow zone to prevent the mutual influence between the anaerobic microorganisms and the aerobic microorganisms.

[0043] The preparation methods of the carbon release fillers 4, the polyurethane fillers 5 and the modified polyurethane fillers 6 are given below.

[0044] The polyurethane fillers are prepared by cutting the hydrophilic polyurethane sponge into small pieces, then soaking and cleaning the polyurethane sponge with pure water, taking out and drying, and then forming the polyurethane fillers.

[0045] The modified polyurethane fillers are prepared by cutting the hydrophilic polyurethane sponge into small pieces, then soaking the polyurethane sponge in a mixed solution of Mn3O4 and adhesive (water-based polyurethane) with a mass ratio of (1-5):(5-20), fully soaking, taking out and drying, and then forming the modified polyurethane fillers.

[0046] The carbon release fillers are prepared by carbonizing corn cob powder, doping nano zero-valent iron powder, and then bonding with polyvinyl alcohol.

[0047] The specific preparation method of the carbon release fillers is as follows:

[0048] 1) the corncob powder is carbonized at a temperature of 200-300 DEG C, the carbonization does not destroy the skeleton of the corncob, and can improve the carbon utilization efficiency, and is more beneficial to microbial degradation and utilization.

[0049] 2) according to the mass ratio of pure water to polyvinyl alcohol (3-5):1, the corresponding polyvinyl alcohol is weighed, and the polyvinyl alcohol is dissolved in a water bath kettle, and the temperature is controlled at 60-80 DEG C, to obtain a polyvinyl alcohol solution;

[0050] 3) according to the mass ratio of (3-10):(80-100), the nano zero-valent iron is mixed with the polyvinyl alcohol solution to obtain a mixed solution, and then according to the mass ratio of polyvinyl alcohol solution:carbonized corncob (0.5-1):(3-5), the carbonized corncob powder is added to the mixed solution, and the carbon release filler is shaped into a spherical shape while hot, and after cooling, it is dried in an oven to obtain the carbon release filler.

[0051] The denitrification mechanism of the three-dimensional biofilm electrode denitrification device driven by solar energy is as follows:

[0052] The sewage is first treated by the carbon release filler in the denitrification zone, and the denitrification is carried out under the action of organic electron donor (corncob) and inorganic electron donor (hydrogen), so that the nitrate nitrogen is removed; then through the ammonia nitrogen removal zone, the polyurethane filler filled in the reactor is used as a carrier for microbial attachment and growth, and the ammonia nitrogen nitrification is removed by aeration. Finally, the modified polyurethane filler in the deep treatment zone further removes the residual nitrogen pollutants. A pollutant monitoring and alarm system is arranged above the deep treatment zone to monitor the COD and TN in the effluent, and if the effluent does not meet the standard, it is recycled to the water distribution area for further treatment until the effluent meets the standard, which significantly improves the applicability of the reactor. The whole reactor realizes the whole process of hydrogen autotrophic denitrification under the action of the electrode, and in combination with the nitrification and denitrification of each zone, the denitrification performance of the whole denitrification is greatly improved.

[0053] The application further provides a three-dimensional biofilm electrode denitrification method based on solar energy driving, comprising the following steps:

[0054] Step 1, the denitrification zone 1, the ammonia nitrogen removal zone 2 and the deep treatment zone 3 are connected in series, and the carbon release filler is placed in the denitrification zone, the polyurethane filler is placed in the ammonia nitrogen removal zone, and the modified polyurethane filler is placed in the deep treatment zone;

[0055] The carbon-releasing filler of carbonized corncob powder is carbonized at a temperature of 200-300 DEG C; polyvinyl alcohol is dissolved by heating in a water bath with pure water and polyvinyl alcohol in a mass ratio of (3-5):1, and the temperature is controlled at 60-80 DEG C to obtain a polyvinyl alcohol solution; nano zero-valent iron and the polyvinyl alcohol solution are mixed in a mass ratio of (3-10):(80-100) to obtain a mixed solution, and then carbonized corncob powder is added into the mixed solution in a mass ratio of polyvinyl alcohol solution:carbonized corncob powder = (0.5-1):(3-5), and the carbon-releasing filler is shaped into a spherical shape while hot, and then dried in an oven after cooling.

[0056] The modified polyurethane filler is prepared by immersing small pieces of polyurethane sponge into a mixed solution of Mn3O4 and a binder (water-based polyurethane) in a mass ratio of (1-5):(5-20), and then drying after sufficient soaking.

[0057] Step 2, water is fed into the water inlet pipe 9 and discharged from the water outlet pipe 10; the ammonia nitrogen concentration of the water fed into the water inlet pipe 9 is 9.00 mg / L-11.50 mg / L, the nitrate nitrogen concentration is 19.50 mg / L-22.00 mg / L, the total nitrogen concentration is 30.00 mg / L-33.50 mg / L, and the COD concentration is 4.50 mg / L-6.00 mg / L;

[0058] Step 3, the solar panel 17 applies electricity to the cathode plate 15 and the anode plate 16 of the microbial separator 8, and the aerator 13 aerates the ammonia nitrogen removal zone 2 through the aerator head 14, so that the dissolved oxygen is maintained at 2.0-4.0 mg / L, and the hydraulic retention time of the entire device is 2-3 hours.

[0059] In this embodiment, the ammonia nitrogen concentration of the water discharged from the denitrification device is 1.19 mg / L-1.74 mg / L, the nitrate nitrogen concentration is 1.46 mg / L-1.83 mg / L, the total nitrogen concentration is 2.83 mg / L-3.54 mg / L, the average removal rate of ammonia nitrogen can reach 86%, the average removal rate of nitrate nitrogen can reach 92%, and the average removal rate of total nitrogen can reach 90%.

[0060] The application will be further described below through specific examples.

[0061] Example 1

[0062] Step 1, the denitrification zone, the ammonia nitrogen removal zone and the advanced treatment zone are connected in series, and fillers are placed in each zone;

[0063] The carbon release filler corn cob powder is carbonized at a temperature of 200℃; polyvinyl alcohol is dissolved in a water bath by heating according to a mass ratio of pure water to polyvinyl alcohol of 3:1, and the temperature is controlled at 70℃ to obtain a polyvinyl alcohol solution; nano zero-valent iron is mixed with the polyvinyl alcohol solution according to a mass ratio of 8:100 to obtain a mixed solution, and then carbonized corn cob powder is added to the mixed solution according to a mass ratio of polyvinyl alcohol solution: carbonized corn cob of 0.5:4, and the carbon release filler is shaped into a spherical shape while hot, and is dried in an oven after cooling.

[0064] Modified polyurethane filler preparation: small pieces of polyurethane sponge are immersed in a mixed solution of Mn3O4 and binder (water-based polyurethane) according to a mass ratio of 1:10, soaked thoroughly, and then taken out and dried.

[0065] Step 2, water is fed from the water inlet pipe and discharged from the water outlet pipe; the ammonia nitrogen concentration is 9.00 mg / L, the nitrate nitrogen concentration is 19.50 mg / L, the total nitrogen concentration is 30.00 mg / L, and the COD concentration is 4.50 mg / L;

[0066] Step 3, the solar panel supplies power to the cathode plate and anode plate of the microbial separator, and the aerator supplies aeration to the ammonia nitrogen removal zone through the aeration head (dissolved oxygen is maintained at 2.0 mg / L), and the hydraulic retention time of the entire device is 3 hours.

[0067] In this embodiment, the ammonia nitrogen concentration of the effluent of the denitrification device is 1.10 mg / L, the nitrate nitrogen concentration of the effluent is 1.40 mg / L, the total nitrogen concentration of the effluent is 2.80 mg / L, the average removal rate of ammonia nitrogen can reach 87.78%, the average removal rate of nitrate nitrogen can reach 92.82%, and the average removal rate of total nitrogen can reach 90.67%.

[0068] Example 2

[0069] Step 1, the denitrification zone, ammonia nitrogen removal zone and advanced treatment zone are connected in series, and fillers are placed in each zone respectively;

[0070] The carbon release filler corn cob powder is carbonized at a temperature of 250℃; polyvinyl alcohol is dissolved in a water bath by heating according to a mass ratio of pure water to polyvinyl alcohol of 4:1, and the temperature is controlled at 60℃ to obtain a polyvinyl alcohol solution; nano zero-valent iron is mixed with the polyvinyl alcohol solution according to a mass ratio of 10:90 to obtain a mixed solution, and then carbonized corn cob powder is added to the mixed solution according to a mass ratio of polyvinyl alcohol solution: carbonized corn cob of 0.8:3, and the carbon release filler is shaped into a spherical shape while hot, and is dried in an oven after cooling.

[0071] Modified polyurethane filler preparation: small pieces of polyurethane sponge are immersed in a mixed solution of Mn3O4 and binder (water-based polyurethane) according to a mass ratio of 3:5, soaked thoroughly, and then taken out and dried.

[0072] Step 2, water is fed from the water inlet pipe and discharged from the water outlet pipe; the ammonia nitrogen concentration of the inlet water is 10.50 mg / L, the nitrate nitrogen concentration is 21.00 mg / L, the total nitrogen concentration is 32.50 mg / L, and the COD concentration is 5.00 mg / L;

[0073] Step 3, the solar panel supplies power to the cathode plate and the anode plate of the microbial separator, and the aerator supplies air to the ammonia nitrogen removal zone through the aeration head (the dissolved oxygen is maintained at 3.0 mg / L), and the hydraulic retention time of the entire device is 2 hours.

[0074] In this embodiment, the ammonia nitrogen concentration of the effluent of the denitrification device is 1.18 mg / L, the nitrate nitrogen concentration is 1.44 mg / L, and the total nitrogen concentration is 2.82 mg / L. The average removal rate of ammonia nitrogen can reach 88.81%, the average removal rate of nitrate nitrogen can reach 93.14%, and the average removal rate of total nitrogen can reach 90.35%.

[0075] Example 3

[0076] Step 1, the denitrification zone, the ammonia nitrogen removal zone and the advanced treatment zone are connected in series, and fillers are placed in each zone respectively;

[0077] The carbon release filler corn cob powder is carbonized at a temperature of 300°C. The polyvinyl alcohol solution is obtained by heating in a water bath to dissolve polyvinyl alcohol at a mass ratio of pure water to polyvinyl alcohol of 5:1, and controlling the temperature at 80°C. The mixed solution is obtained by mixing nano zero-valent iron and polyvinyl alcohol solution at a mass ratio of 3:80. The carbonized corn cob powder is added into the mixed solution, and the carbon release filler is shaped into a spherical shape while hot, and then dried in an oven after cooling.

[0078] The modified polyurethane filler is prepared by immersing small pieces of polyurethane sponge in a mixed solution of Mn3O4 and adhesive (water-based polyurethane) at a mass ratio of 5:20, soaking thoroughly, and then drying.

[0079] Step 2, water is fed from the water inlet pipe and discharged from the water outlet pipe; the ammonia nitrogen concentration of the inlet water is 11.50 mg / L, the nitrate nitrogen concentration is 22.00 mg / L, the total nitrogen concentration is 33.50 mg / L, and the COD concentration is 6.00 mg / L;

[0080] Step 3, the solar panel supplies power to the cathode plate and the anode plate of the microbial separator, and the aerator supplies air to the ammonia nitrogen removal zone through the aeration head (the dissolved oxygen is maintained at 4.0 mg / L), and the hydraulic retention time of the entire device is 2.5 hours.

[0081] In the embodiment, the ammonia nitrogen concentration of the effluent of the denitrification device is 1.19 mg / L, the nitrate nitrogen concentration of the effluent is 1.46 mg / L, the total nitrogen concentration of the effluent is 2.83 mg / L, the average removal rate of ammonia nitrogen can reach 89.64%, the average removal rate of nitrate nitrogen can reach 93.36%, and the average removal rate of total nitrogen can reach 91.54%.

[0082] As can be seen from the above embodiment, the corn cob is pretreated by mechanical crushing + carbonization treatment method to serve as the core carbon release substrate of the carbon release filler, the polyvinyl alcohol is used as the binder to bond the carbonized corn cob powder, the polyvinyl alcohol and the nano zero-valent iron powder into a spherical carbon release filler, the proportions of the components of the carbonized corn cob powder, the polyvinyl alcohol and the nano zero-valent iron are subjected to microbial domestication, the ammonia nitrogen concentration of the effluent of the denitrification device is not higher than 1.19 mg / L, the nitrate nitrogen concentration of the effluent is not higher than 1.46 mg / L, the total nitrogen concentration of the effluent is not higher than 2.83 mg / L, the average removal rate of ammonia nitrogen can reach 88.41%, the average removal rate of nitrate nitrogen can reach 93.11%, and the average removal rate of total nitrogen can reach 90.85%. Meanwhile, the COD of the effluent is less than 1.50 mg / L, and there is no secondary pollution.

[0083] The present application solves the problem of denitrification in low C / N water bodies, produces hydrogen by electrolysis of water, and combines hydrogen autotrophic denitrifying bacteria to achieve efficient removal of nitrogen pollution. Using solar energy as a renewable energy source, the electrode generates hydrogen in the water, providing the electron donor required by hydrogen autotrophic denitrifying bacteria, so that efficient denitrification can still be achieved under low carbon source conditions. To further compensate for the limitation of insufficient carbon source on the denitrification process, the present application introduces agricultural waste corn cob as a slow-release carbon source. After low-temperature carbonization treatment, the corn cob serves as a sustainable carbon source, slowly releasing organic matter, not only providing a continuous carbon source for heterotrophic denitrification, but also complementing the hydrogen autotrophic denitrification process to form a synergistic effect. The present application not only realizes hydrogen autotrophic denitrification under aerobic conditions, but also effectively improves the denitrification efficiency and stability of the system, achieving efficient removal of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in low C / N reservoir water bodies. The present application provides an economic, environmentally friendly and sustainable solution for denitrification treatment of low C / N water bodies, and is suitable for the field of efficient denitrification of low C / N reservoir water bodies.

[0084] The present application is not limited to the above embodiments, and based on the technical solutions disclosed in the present application, those skilled in the art can make some substitutions and modifications to some technical features without creative labor, and these substitutions and modifications are within the protection scope of the present application.

Claims

1. A solar-driven three-dimensional biofilm electrode denitrification device, characterized in that: The microbial separator (8) is divided from bottom to top into a denitrification zone (1), an ammonia nitrogen removal zone (2), and a deep treatment zone (3); the denitrification zone (1) is filled with a carbon-releasing filler (4), the ammonia nitrogen removal zone (2) is filled with a polyurethane filler (5), and the deep treatment zone (3) is filled with a modified polyurethane filler (6); The modified polyurethane filler is prepared by cutting a hydrophilic polyurethane sponge into small pieces, then immersing the polyurethane sponge in a mixture of Mn3O4 and aqueous polyurethane in a mass ratio of (1-5): (5-20), fully immersing the mixture, taking it out and drying it, thereby forming the modified polyurethane filler; Carbon-releasing filler production includes: 1) Carbonize corn cob powder at a temperature of 200-300℃; 2) Prepare a polyvinyl alcohol solution at a temperature of 60-80°C with a mass ratio of pure water to polyvinyl alcohol of (3-5):1; 3) According to the mass ratio of (3~10): (80~100), the nano Zero-valent iron and mixing with polyvinyl alcohol solution to obtain a mixed solution, then adding carbonized corn cob powder to the mixed solution in a mass ratio of polyvinyl alcohol solution: carbonized corn cob = (0.5-1): (3-5), shaping the mixture into a spherical carbon-releasing filler while hot, and drying it in an oven after cooling to obtain a carbon-releasing filler; The denitrification zone (1) at the bottom of the microbial separator (8) is connected to the water inlet pipe (9); a water distribution zone (7) is provided between the denitrification zone (1) and the ammonia nitrogen removal zone (2), and the water distribution zone (7) is connected to the water outlet pipe (10); A cathode plate (15) and an anode plate (16) connected to a solar panel (17) are inserted into the microbial separator (8); an aeration device is provided in the ammonia nitrogen removal zone (2); The sewage in the microbial separator (8) is subjected to a full process of hydrogen autotrophic denitrification under the action of various fillers, electrode electrolysis and aeration.

2. The solar-driven three-dimensional biofilm electrode denitrification device according to claim 1 is characterized in that: The production of polyurethane filler includes: cutting a hydrophilic polyurethane sponge into small pieces, fully soaking and cleaning the polyurethane sponge with pure water, taking it out and drying it to form the polyurethane filler.

3. The solar-driven three-dimensional biofilm electrode denitrification device according to claim 1 is characterized in that: A microbial separator is provided in the middle of the water distribution area (7). The water distribution area (7) is connected to the water outlet pipe (10) via a return pipe (11). A return pressure pump (12) is provided on the return pipe (11).

4. The solar-driven three-dimensional biofilm electrode denitrification device according to claim 1 is characterized in that: The cathode plate (15) and the anode plate (16) are platinum-coated titanium electrodes.

5. The solar-driven three-dimensional biofilm electrode denitrification device according to claim 1 is characterized in that: The aeration device includes an aeration head (14) connected to an aerator (13) in the ammonia nitrogen removal zone (2).

6. The solar-driven three-dimensional biofilm electrode denitrification device according to claim 1 is characterized in that: A perforated partition is provided between the ammonia nitrogen removal zone (2) and the deep treatment zone (3); and a pollutant monitoring and alarm device (18) is provided above the deep treatment zone (3).

7. The denitrification method of the solar-driven three-dimensional biofilm electrode denitrification device according to any one of claims 1 to 6, characterized in that: include: (a) The denitrification zone (1), the ammonia nitrogen removal zone (2) and the deep treatment zone (3) are connected in series, and a carbon-releasing filler (4) is placed in the denitrification zone (1), a polyurethane filler (5) is placed in the ammonia nitrogen removal zone (2), and a modified polyurethane filler (6) is placed in the deep treatment zone (3); The carbon-releasing filler corn cob powder is carbonized at a temperature of 200-300 °C; the polyvinyl alcohol is dissolved in a water bath at a mass ratio of pure water to polyvinyl alcohol of (3-5):1, and the temperature is controlled at 60-80 °C to obtain a polyvinyl alcohol solution; the nanoparticles are added at a mass ratio of (3-10): (80-100) Zero-valent iron Mixing with polyvinyl alcohol solution to obtain a mixed solution, then adding carbonized corn cob powder to the mixed solution according to the mass ratio of polyvinyl alcohol solution: carbonized corn cob = (0.5~1): (3~5), shaping it into a spherical carbon-releasing filler while hot, and drying it in an oven after cooling; Preparation of modified polyurethane filler: soak a small piece of polyurethane sponge in a mixture of Mn3O4 and aqueous polyurethane in a mass ratio of (1-5): (5-20), soak it fully, then take it out and dry it; (b) water is introduced from the water inlet pipe (9) and discharged from the water outlet pipe (10); the concentration of ammonia nitrogen, nitrate nitrogen, total nitrogen and COD in the inlet water is controlled; (c) The solar panel (17) supplies power to the cathode plate (15) and the anode plate (16) of the microbial separator (8) for electrolysis, and the aeration device aerates the ammonia nitrogen removal zone (2) to control the hydraulic retention time for hydrogen autotrophic denitrification of the entire sewage process.

8. The solar-driven three-dimensional biofilm electrode denitrification method according to claim 7, characterized in that: Influent ammonia nitrogen concentration is 9.00 mg / L-11.50 mg / L, nitrate nitrogen concentration is 19.50 mg / L-22.00 mg / L, total nitrogen concentration is 30.00 mg / L-33.50 mg / L, COD concentration is 4.50 mg / L-6.00 mg / L; Aeration maintains dissolved oxygen at 2.0-4.0 mg / L; The hydraulic retention time is 2 to 3 hours.

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