A low-carbon source sewage treatment device and method

Abstract

The present application discloses a low-carbon source sewage treatment device and method, comprising: a box body defining a box body cavity; an anode assembly disposed in the box body cavity and configured to be connected to the positive electrode of a power source; and a cathode assembly disposed in the box body cavity and configured to be connected to the negative electrode of the power source; wherein, the anode assembly and / or the cathode assembly includes a first titanium mesh layer, a first porous fiber cotton layer, a first mixed filler layer, a second titanium mesh layer, a second mixed filler layer, a second porous fiber cotton layer and a third titanium mesh layer. The sewage treatment device of the present application utilizes the nascent active hydrogen generated by electrolyzing water on the cathode assembly as an autotrophic denitrification electron donor, and can achieve efficient synchronous nitrogen and phosphorus removal from low-carbon source sewage in the same sewage treatment device without the need to additionally add an organic carbon source.

Description

Technical Field

[0001] The present application relates to the technical field of water pollution control, and more particularly to a low-carbon source sewage treatment device and method. Background Art

[0002] Due to the growth of the social population and the rapid development of industrial and agricultural economies, the large-scale discharge of domestic sewage, aquaculture tail water, and nitrogen-containing industrial wastewater has caused the concentration of nitrogen pollutants in natural river and lake waters to continuously accumulate, resulting in the aggravation of water eutrophication, the outbreak of cyanobacterial blooms, and even the phenomenon of black and odorous water bodies, seriously threatening the ecological health of water bodies and water use safety. The biological nitrification-denitrification process is currently the main means of eliminating nitrogen pollution in the water treatment process. Among them, denitrifying microorganisms use organic matter as an energy (electron donor) source under anaerobic and anoxic conditions to convert NO3 - -N into N2, thereby achieving the purpose of eliminating NO3 - -N pollution. In the traditional biological nitrification-denitrification process, an appropriate carbon-nitrogen ratio (i.e., C / N ratio or carbon source) is the key for efficient nitrogen removal by denitrifying bacteria. The carbon-nitrogen ratio (C / N) is the molar ratio of carbon and nitrogen elements in the influent sewage. Under some conditions, the carbon-nitrogen ratio refers to the ratio of BOD to TN, and in some cases, COD / TN can also be used as the value of the carbon-nitrogen ratio. Generally speaking, when the BOD5 / TN ratio in sewage is higher than 5, denitrifying bacteria can effectively play their denitrification role. The organic matter in sewage with a low C / N ratio is not sufficient for denitrifying microorganisms to completely remove NO3 - -N pollution, so the NO3 - -N pollution cannot be effectively controlled.

[0003] However, domestic sewage in the southern region and most rural domestic sewage usually have the characteristics of a low carbon-nitrogen ratio (C / N). In the case of insufficient carbon source in the influent sewage, the denitrification process in the traditional nitrification-denitrification nitrogen removal process lacks the required electron donor, which is likely to cause the accumulation of nitrate nitrogen and nitrite nitrogen, and the nitrogen removal effect is not good; while excessive addition of organic carbon source makes it difficult to ensure the effluent COD. At present, there is still a lack of effective sewage treatment technologies that can produce efficient nitrogen and phosphorus removal effects under the condition of low carbon-nitrogen ratio influent. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present application is to provide a low-carbon source sewage treatment device and method for solving the problem of inability to efficiently remove nitrogen and phosphorus under the condition of low carbon-nitrogen ratio influent in the prior art.

[0005] To achieve the above purpose, the present application provides a low-carbon source sewage treatment device, including:

[0006] A box body that defines a box cavity;

[0007] An anode assembly, disposed in the cavity of the box body and configured to be connected to the positive electrode of the power supply; and

[0008] A cathode assembly, disposed in the cavity of the box body and configured to be connected to the negative electrode of the power supply;

[0009] Wherein, the anode assembly and / or the cathode assembly includes a first titanium mesh layer, a first porous fiber cotton layer, a first mixed filler layer, a second titanium mesh layer, a second mixed filler layer, a second porous fiber cotton layer, and a third titanium mesh layer arranged in sequence.

[0010] Preferably, the first titanium mesh layer, the second titanium mesh layer, and the third titanium mesh layer are diamond-shaped titanium meshes; and / or

[0011] The thicknesses of the first titanium mesh layer and the third titanium mesh layer are both greater than the thickness of the second titanium mesh layer; and / or, the mesh sizes of the first titanium mesh layer and the third titanium mesh layer are both greater than the mesh size of the second titanium mesh layer.

[0012] Preferably, the first mixed filler layer and the second mixed filler layer are a mixture of PHBV and short carbon fiber, and the mass ratio of the short carbon fiber to PHBV is 8:1 to 10:1.

[0013] Preferably, the box body has a left side wall and a right side wall arranged opposite to each other; a water inlet is provided at the upper part of the left side wall, and a water outlet is provided at the upper part of the right side wall.

[0014] Preferably, the low-carbon source sewage treatment device further includes an iron plate disposed in the cavity of the box body, and the anode assembly is located between the iron plate and the cathode assembly.

[0015] Preferably, the box body has a front side wall and a rear side wall arranged opposite to each other; the iron plate, the anode assembly, and the cathode assembly are respectively installed between the front side wall and the rear side wall.

[0016] Preferably, the low-carbon source sewage treatment device further includes a cover member, the box body further has an opening communicating with the cavity of the box body, and the cover member covers the opening;

[0017] The anode assembly includes a first anode assembly, a second anode assembly, and a third anode assembly arranged at intervals; the cathode assembly includes a first cathode assembly, a second cathode assembly, and a third cathode assembly arranged at intervals;

[0018] The iron plate, the second anode assembly, the first cathode assembly, the third cathode assembly are in contact with the cover member and are spaced apart from the bottom wall of the box body by a first distance; the first anode group, the third anode assembly, and the second cathode assembly are in contact with the bottom wall of the box body and are spaced apart from the cover member by a second distance.

[0019] Preferably, a number of first fixing components are provided on the front side wall and the rear side wall to mount the first anode group, the third anode component, and the second cathode component. The first fixing component includes a first module and a second module arranged at intervals. The first anode component, the third anode component, and the second cathode component are inserted between the corresponding first module and second module, and the lowermost first module and second module abut against the bottom wall;

[0020] A number of the first fixing components and second fixing components are further provided on the front side wall and the rear side wall to mount the iron plate, the second anode component, the first cathode component, and the third cathode component. The second fixing component includes a third module, a fourth module arranged at intervals, and a fifth module located between the third module and the fourth module. The iron plate, the second anode component, the first cathode component, and the third cathode component are inserted between the corresponding third module and fourth module and are supported by the corresponding fifth module. The bottom of the fifth module is spaced from the bottom wall by the first distance.

[0021] Preferably, an anode area and a cathode area are formed in the cavity of the box body. The iron plate and the anode component are located in the anode area, and the cathode component is located in the cathode area. An aeration device is further provided in the anode area.

[0022] This application also provides a low-carbon source sewage treatment method, including:

[0023] 1) Provide the above low-carbon source sewage treatment device;

[0024] 2) Make the low-carbon source sewage enter the cavity of the box body from the water inlet, and the sewage water flow sequentially flows through the iron plate, the first anode component, the second anode component, the third anode component, the first cathode component, the second cathode component, and the third cathode component in a vertically folded flow direction, and finally flows out from the water outlet.

[0025] The low-carbon source sewage treatment device provided by this application has the following technical effects:

[0026] 1. This application can achieve efficient synchronous denitrification and phosphorus removal of low-carbon source sewage in a sewage treatment device, and has a simple structure, low maintenance cost, and does not require complex management and personnel care.

[0027] 2. The sewage treatment device of this application uses the nascent active hydrogen generated by electrolyzing water on the cathode component as the autotrophic denitrification electron donor, and can achieve denitrification of low-carbon source sewage without adding an additional organic carbon source as the electron donor.

[0028] 3. The cathode assembly of this application constructs a dense attachment active carrier for autotrophic denitrifying bacteria by using a titanium mesh layer, a porous fiber cotton layer, and a mixed filler layer. It has high biocompatibility, and a large number of microorganisms can attach and grow on the cathode assembly, and efficient autotrophic denitrification and nitrogen removal can be carried out under hydrogen autotrophic conditions.

[0029] 4. The ferrous ions electrolyzed from the iron plate located in the anode area of this application and OH - in the sewage can cause a large amount of synchronous deposition and removal of phosphate radicals.

[0030] 5. The staggered arrangement of the electrode assembly and the iron plate in this application makes the sewage flow entering the box body flow in an up-and-down zigzag direction, increasing the contact surface between the sewage and the electrode assembly and improving the sewage treatment effect.

[0031] 6. In the electrode assembly: The titanium mesh layer increases the conductivity of the electrode assembly, makes the current distribution uniform, and is beneficial to the attachment and growth of microorganisms; the porous fiber cotton layer increases the specific surface area of the electrode assembly, further increasing the attachment sites for microorganisms, especially facilitating the enrichment of a large number of autotrophic denitrifying bacteria; the addition of short-cut carbon fibers in the mixed filler layer further increases the specific surface area of the electrode assembly and enhances the current conduction, making the current distribution uniform throughout the sewage treatment device; the PHBV in the mixed filler layer is a solid-phase carbon source, which can be hydrolyzed by the extracellular enzymes of microorganisms and used as a carbon source and electron donor in the denitrification process, realizing the autotrophic-heterotrophic synergistic denitrification of the sewage treatment device and further improving the nitrogen removal efficiency.

[0032] The following will further illustrate the concept, specific structure, and technical effects generated by this application in conjunction with the drawings to fully understand the purpose, features, and effects of this application. Description of the Drawings

[0033] Figure 1 is a top view of a low-carbon source sewage treatment device of this application.

[0034] Figure 2 is a front view of a low-carbon source sewage treatment device of this application.

[0035] Figure 3 is Figure 1 an enlarged view of part A in

[0036] Among them, 10 - box body, 11 - box body cavity, 12 - left side wall, 13 - right side wall, 14 - rear side wall, 15 - front side wall; 16 - water inlet, 17 - water outlet, 18 - bottom wall;

[0037] 20 - iron plate;

[0038] 31 - first anode assembly, 32 - second anode assembly, 33 - third anode assembly;

[0039] 41 - First cathode assembly, 42 - Second cathode assembly, 43 - Third cathode assembly, 401 - First titanium mesh layer, 402 - First porous fiber cotton layer, 403 - First mixed filler layer, 404 - Second titanium mesh layer, 405 - Second mixed filler layer, 406 - Second porous fiber cotton layer, 407 - Third titanium mesh layer;

[0040] 51 - First circular aeration disk, 52 - Second circular aeration disk;

[0041] 61 - First module, 62 - Second module;

[0042] 71 - Third module, 72 - Fourth module, 73 - Fifth module. Detailed implementation manners

[0043] The following specific examples illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0044] It should be understood that although directional terms such as "upper", "lower", "left", "right", "inner", "outer", "bottom", etc. are used in the present application to describe various exemplary structural parts and elements in the present application, these terms are only used for the convenience of description, and these terms are determined based on the exemplary orientations shown in the drawings. Since the embodiments disclosed in the present application can be arranged in different directions, these directional terms are only for illustration and should not be regarded as limitations.

[0045] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner. Therefore, only the components related to the present application are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0046] For the purpose of illustration, some exemplary embodiments of the present application are described. It should be understood that the present application can be implemented in other ways not specifically shown in the drawings.

[0047] The present application provides a low-carbon source sewage treatment device. As an example, the present application provides a specific structure and lists specific dimensions during the description. It should be understood that this is entirely for a more complete and detailed understanding of the present application and does not constitute a limitation of the present application. The specific structure and dimensions can be adjusted according to the actual situation.

[0048] The low-carbon source sewage mentioned in the present application is defaulted to sewage with a BOD5 / TN ratio less than or equal to 5.

[0049] Embodiment 1

[0050] This embodiment provides an implementation manner of the low-carbon source sewage treatment device. Figure 1 and Figure 2 shows the specific structure from different perspectives. It includes a box body 10 and a cover member (not shown in the figure). The box body 10 has a left side wall 12, a right side wall 13, a front side wall 15, a rear side wall 14, and a bottom wall 18. The left side wall 12, the right side wall 13, the front side wall 15, the rear side wall 14, and the bottom wall 18 enclose a box body cavity 11, and the cover member covers the upper opening of the box body cavity 11. The materials of the box body 10 and the cover member can be selected as plexiglass or PVC. Preferably, a layer of black light-shielding paper is pasted on the outer wall of the box body to prevent the growth of algae. As an example, the box body is 65 cm long, 20 cm wide, and 40 cm high, the bottom thickness is 1 cm, and the side wall thickness is 0.5 cm. Then the inner length of the box body is 64 cm, the width is 19 cm, and the height is 39 cm.

[0051] Figure 1 and Figure 2 Although the low-carbon source sewage treatment device of the present application is shown as a cuboid structure, it should be understood that the structure of the box body is not specially limited. Typical but non-limiting box body structures, such as cylinders, cuboids, cubes, prisms, spheres, hemispheres, or some other irregular-shaped bodies, are all applicable.

[0052] Inside the box cavity 11, there are arranged an iron plate 20, a first anode assembly 31, a second anode assembly 32, a third anode assembly 33, a first cathode assembly 41, a second cathode assembly 42 and a third cathode assembly 43 in sequence from left to right. The iron plate 20, the first anode assembly 31, the second anode assembly 32 and the third anode assembly 33 are connected to the positive pole of the power supply and are located in the anode area, that is, the aerobic nitrification area; the first cathode assembly 41, the second cathode assembly 42 and the third cathode assembly 43 are connected to the negative pole of the power supply and are located in the cathode area, that is, the denitrification area. More specifically, the power supply includes an AC-DC converter, a voltage regulator, an anode waterproof wire and a cathode waterproof wire. There is a through hole opened on the cover part. The anode waterproof wire is connected to the first anode assembly 31, the second anode assembly 32, the third anode assembly 33 and the iron plate 20 through the through hole, and the cathode waterproof wire is connected to the first cathode assembly 41, the second cathode assembly 42 and the third cathode assembly 43 through the through hole. Conventional alligator clips can be used during connection.

[0053] There is a water inlet 16 provided on the left side wall 12 of the box body 10. The water inlet 16 is preferably arranged at the upper part of the left side wall 12. The water inlet 16 is connected to a water inlet pipe to enable sewage to flow into the box cavity 11. As an example, the diameter of the water inlet is 0.5 cm, the distance from the center of the water inlet to the bottom wall of the box body 10 is 34.25 cm, and the distance from the center of the water inlet to the upper part of the box body 10 is 4.75 cm. This arrangement of the water inlet 16 is because the left end of the low-carbon source sewage treatment device is the aerobic nitrification area. Compared with inletting water from the lower part, when inletting water from the upper part, the position of the water inlet 16 is connected to the outside air, which has a certain supplement to the dissolved oxygen content of the sewage and is more conducive to the degradation of ammonia nitrogen by nitrifying bacteria.

[0054] There is a water outlet 17 provided on the right side wall 13 of the box body 10. The water outlet 17 is preferably arranged at the upper part of the right side wall 13. The water outlet 17 is connected to a water outlet pipe to enable the treated sewage to be discharged from the box cavity 11. As an example, the diameter of the water outlet is 0.5 cm, the distance from the center of the water outlet to the bottom wall of the box body 10 is 34.25 cm, and the distance from the center of the water outlet to the upper part of the box body 10 is 4.75 cm. This arrangement of the water outlet 17 can make the sewage have a longer flow path in the system, be in more sufficient contact with the electrode assembly and microorganisms, and improve the sewage treatment effect.

[0055] In order to make the sewage flow in a vertically folded flow direction in the box cavity 11, the iron plate 20, the first anode assembly 31, the second anode assembly 32, the third anode assembly 33, the first cathode assembly 41, the second cathode assembly 42 and the third cathode assembly 43 are arranged at different heights. The iron plate 20, the second anode assembly 32, the first cathode assembly 41, and the third cathode assembly 43 are in contact with the cover member and are spaced from the bottom wall 18 of the box body 10 by a first distance; the first anode group 31, the third anode assembly 33, and the second cathode assembly 42 are in contact with the bottom wall 18 of the box body 10 and are spaced from the cover member by a second distance. With such an arrangement, there are gaps at both the bottom and the top of the box body 10, and the water flow can flow in a vertically folded flow direction, increasing the contact area between the sewage and the electrode assembly and improving the sewage treatment effect.

[0056] The first distance is preferably equal to the second distance, and of course, they can also be set to be different. As an example, the first distance is 4 cm and the second distance is 4 cm.

[0057] A number of first fixing components are provided on the front side wall 15 and the rear side wall 14 to install the first anode assembly 31, the third anode assembly 33, and the second cathode assembly 42. Taking the first anode assembly 31 as an example for specific illustration, a number of first fixing components are respectively provided at positions corresponding to the first anode assembly 31 on the front side wall 15 and the rear side wall 14, preferably 2, and of course, several more can also be provided. The first fixing component includes a first module 61 and a second module 62 arranged at intervals, and the first anode assembly 31 is sandwiched between the first module 61 and the second module 62. The lowermost first module 61 and second module 62 are in contact with the bottom wall 18 to enable the first anode assembly 31 to be stably in contact with the bottom 18. The third anode assembly 33 and the second cathode assembly 42 are fixed to the front side wall 15 and the rear side wall 14 in a manner similar to that of the first anode assembly 31, which will not be elaborated here.

[0058] A number of first fixing components and second fixing components are also provided on the front side wall 15 and the rear side wall 14 to mount the iron plate 20, the second anode assembly 32, the first cathode assembly 41, and the third cathode assembly 43. Taking the first cathode assembly 41 as an example for specific description, a number of first fixing components and second fixing components are respectively provided at positions corresponding to the first cathode assembly 41 on the front side wall 15 and the rear side wall 14. Preferably, 1 first fixing component and 1 second fixing component are provided on one side wall. Of course, several more can also be provided. The second fixing component includes a third module 71, a fourth module 72 arranged at intervals, and a fifth module 73 located between the third module 71 and the fourth module 72. The third module 71, the fourth module 72, and the fifth module 73 form a "concave" shape structure. The first cathode assembly 41 is located between the third module 71 and the fourth module 72 and is supported by the fifth module. The bottom of the fifth module 73 is spaced from the bottom wall 18 by a first distance. The iron plate 20, the second anode assembly 32, and the third cathode assembly 43 are fixed to the front side wall 15 and the rear side wall 14 in a manner similar to that of the first cathode assembly 41, which will not be elaborated here.

[0059] The iron plate 20 is arranged at the leftmost end of the box cavity 11. As an example, the height of the iron plate is 34 cm. The main function of the iron plate is to form ferrous ions through electrolysis, so that PO4 in the sewage 3- forms a complex deposit and is removed in an alkaline environment; secondly, iron is an essential element for the growth of microorganisms. Ferrous ions can increase the permeability of the cell membrane, thereby accelerating the absorption rate of nutrients and promoting nitrification and denitrification. By arranging the iron plate at the leftmost end, the ferrous ions released by the iron plate can flow along the water flow direction to promote nitrification and denitrification of the microorganisms in the subsequent electrode assemblies.

[0060] An aeration device is also arranged at the bottom of the box cavity 11. The aeration device is located in the anode area and is used to discharge a large amount of air evenly from the bottom upwards to maintain an aerobic environment in the anode area. It should be understood that existing devices capable of realizing aeration to increase the dissolved oxygen content in the anode area are applicable to this application. As an example, the aeration device can be a second circular aeration disc 52 located between the first anode assembly 31 and the second anode assembly 32 and a first circular aeration disc 51 located between the second anode assembly 32 and the third anode assembly 33. The aeration discs adopt nano-level air discs with a diameter of 3.5 cm. The two aeration discs are connected to the same double-hole air pump, and the air pump is also provided with a butterfly valve and a check valve to control the gas flow rate and control the dissolved oxygen in the anode area to be 4 mg / L to 5 mg / L.

[0061] The structures of the first anode assembly 31, the second anode assembly 32, the third anode assembly 33, the first cathode assembly 41, the second cathode assembly 42, and the third cathode assembly 43 in this application are the same, except for some differences in size. Here, the third cathode assembly 43 is taken as an example for specific description. The third cathode assembly 43 is a multi-layer structure. Figure 3 shows Figure 1 an enlarged view of part A in Figure 3 which shows the specific structure of each layer. As

[0062] shown, the third cathode assembly 43 sequentially includes a first titanium mesh layer 401, a first porous fiber cotton layer 402, a first mixed filler layer 403, a second titanium mesh layer 404, a second mixed filler layer 405, a second porous fiber cotton layer 406, and a third titanium mesh layer 407 from left to right.

[0063] The thickness of the first titanium mesh layer 401 is greater than that of the second titanium mesh layer 404, and the thickness of the third titanium mesh layer 407 is greater than that of the second titanium mesh layer 404; the mesh size of the first titanium mesh layer 401 is greater than that of the second titanium mesh layer 404, and the mesh size of the third titanium mesh layer 407 is greater than that of the second titanium mesh layer 404.

[0064] The first titanium mesh layer 401 and the third titanium mesh layer 407 have the same structure, both being diamond-shaped titanium meshes. As an example, their height is 34 cm, thickness is 1.5 mm, and the mesh specification is 2 mm × 6 mm; the second titanium mesh layer 404 is also a diamond-shaped titanium mesh. As an example, its height is 34 cm, thickness is 0.5 mm, and the mesh specification is 0.8 mm × 1.5 mm. The diamond-shaped titanium mesh can achieve uniform current distribution. The configuration of the three-layer diamond-shaped titanium meshes increases the conductivity of the electrode assembly, and the diamond-shaped mesh holes are beneficial to the attachment and growth of microorganisms.

[0065] The components of the first mixed filler layer 403 and the second mixed filler layer 405 are the same, both being a mixture of PHBV and short carbon fibers. The ratio of short carbon fibers to PHBV is about 8:1 to 10:1. The thickness of the first mixed filler layer 403 and the second mixed filler layer 405 is 0.2 - 0.3 cm. The average length of the short carbon fibers is 0.3 cm, and the average particle size of PHBV is 0.3 cm. As an example, the height of the first mixed filler layer 403 and the second mixed filler layer 405 is 33 cm. The addition of short carbon fibers further increases the specific surface area of the electrode assembly and enhances current conduction, making the current distribution in the entire sewage treatment device uniform. PHBV (synthetic biodegradable polymer) is a solid-phase carbon source, which can be hydrolyzed by extracellular enzymes in the biofilm attached to its surface, decomposing PHBV into soluble small-molecule organic matter. Most of the small-molecule organic matter is used as a carbon source and electron donor in the microbial denitrification process. The treatment of low-carbon-source sewage in this application mainly relies on autotrophic denitrifying bacteria. Adding a small amount of solid-phase carbon source can enable the sewage treatment device to achieve autotrophic-heterotrophic synergistic denitrification and realize efficient nitrogen removal. The solid carbon source decomposes slowly under the action of microorganisms, which can achieve the purpose of slowly releasing the carbon source and avoid causing secondary pollution.

[0066] In this application, the structures and sizes of the first cathode assembly 41 and the second anode assembly 32 are the same as those of the third cathode assembly 43. The structures of the first anode assembly 31, the third anode assembly 33, and the second cathode assembly 42 are the same as those of the third cathode assembly 43, except for slight differences in size. The height of the three-layer titanium mesh in the first anode assembly 31, the third anode assembly 33, and the second cathode assembly 42 is 35 cm, and the height of the porous fiber cotton layer and the mixed filler layer is 34 cm.

[0067] In the electrode assembly of this application, the height of the titanium mesh layer is selected to be 1 cm larger than the height of the porous fiber cotton layer and the mixed filler layer, which is conducive to more stable connection with the wire. Especially when using alligator clips to connect with the electrode wire, it is easier to clamp the electrode assembly.

[0068] In the above embodiments of this application, the low-carbon-source sewage treatment device is respectively provided with 3 cathode assemblies and 3 anode assemblies. It should be understood that 1 or more can also be designed according to needs or actual situations. It should also be understood that the specific dimensions related to the device mentioned above are only for the convenience of introduction and do not constitute a limitation of this application. As long as the functions of this application can be achieved, those skilled in the art can adjust arbitrarily, all within the scope of this application. It should also be understood that when the structure and size of the box body are adjusted, the sizes of the iron plate and the electrode assembly in the box body can be adjusted accordingly.

[0069] Combined with the above description, the reason why the sewage treatment device of the present application can achieve low-carbon source sewage treatment is essentially as follows: After applying an electric current, the sewage treatment device of the present application electrolyzes water on the cathode assembly to generate nascent active hydrogen as an autotrophic denitrification electron donor, without the need to additionally add an organic carbon source as an electron donor; and the cathode assembly uses a porous fiber cotton layer, a titanium mesh layer, and a mixed filler layer to construct a dense attachment active carrier for autotrophic denitrifying bacteria, which has high biocompatibility. A large number of microorganisms can attach and grow on the cathode assembly, and efficient autotrophic denitrification nitrogen removal is carried out under hydrogen autotrophic conditions; at the same time, ferrous ions generated by electrolyzing the iron plate in the anode area and OH in the sewage - can cause a large amount of synchronous deposition removal of phosphate radicals.

[0070] The working principle of the low-carbon source sewage treatment device of the present application is as follows: When starting, activated sludge cultured under nitrifying sludge culture conditions is inoculated on the surface of the anode assembly, and activated sludge cultured under denitrifying sludge culture conditions is inoculated on the surface of the cathode assembly. After a period of biofilm acclimation, a biofilm will form on the surface of the electrode assembly. When treating low-carbon source sewage, an oxygen evolution reaction occurs on the surface of the anode assembly, and nitrifying bacteria use the evolved oxygen to carry out nitrification reaction on NH4 + -N; a reduction reaction occurs on the surface of the cathode assembly, water is electrolyzed to generate nascent active hydrogen, and autotrophic denitrifying bacteria on the biofilm use it as an electron donor to carry out efficient denitrification nitrogen removal under low-carbon source conditions; in addition, ferrous ions generated by electrolyzing the iron plate and OH in the sewage - can cause a large amount of synchronous deposition removal of phosphate radicals in the sewage.

[0071] The low-carbon source sewage treatment device of the present application has the characteristics of low energy consumption, high generation and utilization rate of active hydrogen, and can cleanly and efficiently treat total nitrogen and total phosphorus in sewage.

[0072] Example 2

[0073] This example provides an implementation method of a low-carbon source sewage treatment method, which includes using the low-carbon source sewage treatment device in Example 1. The start-up method of this device is as follows: Dilute the concentrated activated sludge taken from the aeration tank of the sewage treatment plant, culture it in the laboratory for two weeks under nitrifying sludge culture conditions and denitrifying sludge culture conditions respectively, and then inoculate it into the low-carbon source sewage treatment device in Example 1. The anode assembly is inoculated with nitrifying sludge, and the cathode assembly is inoculated with denitrifying sludge. After about one week of stable biofilm formation, power-on acclimation is carried out until the stable period is reached.

[0074] After the start-up of the low-carbon source sewage treatment device, the operation method is as follows: The artificially configured low-carbon source sewage is introduced into the water inlet tank. The low-carbon source sewage uses glucose as the carbon source, NaNO3 and NH4Cl as the nitrogen source, and KH2PO4 as the phosphorus source. Appropriate trace elements are added (configured with MgSO4·7H2O, CaCl2, ZnSO4·7H2O, etc.). The DC power supply is turned on, and the current intensity is adjusted to 10 mA - 15 mA. The water outlet from the water inlet tank enters the water inlet 16 of the box body 10, and the flow rate is controlled by the flow rate regulating valve. The sewage flow flows through the iron plate 20, the first anode assembly 31, the second anode assembly 32, the third anode assembly 33, the first cathode assembly 41, the second cathode assembly 42, and the third cathode assembly 43 in a vertically folded flow direction. The water level in the box body 10 is controlled at 37 cm - 39 cm. After the sewage stays in the reactor for 8 h - 12 h, the water discharged from the water outlet 17 can meet the drainage requirements. When treating low-carbon source sewage: An oxygen evolution reaction occurs on the surface of the anode assembly in the cavity 11 of the box body, and nitrifying bacteria use the evolved oxygen to carry out nitrification reaction on NH4 + -N; A reduction reaction occurs on the surface of the cathode assembly, water is electrolyzed to generate nascent active hydrogen, and autotrophic denitrifying bacteria on the biofilm use it as an electron donor to carry out efficient denitrification and nitrogen removal under the condition of low-carbon source. In addition, extracellular enzymes in the biofilm will decompose PHBV into soluble small-molecule organic matter to be used as the carbon source and electron donor in the denitrification process, enabling the sewage treatment device to achieve autotrophic-heterotrophic synergistic denitrification and further improving the nitrogen removal efficiency; The electrolysis of the iron plate will generate ferrous ions, which react with OH in the sewage - to achieve the effect of phosphorus removal by synchronous deposition of phosphate radicals in a large amount.

[0075] The following table shows the experimental results of sewage treatment by the low-carbon source sewage treatment device according to Example 1:

[0076] Table 1 - Treatment results of the first low-carbon source sewage (C / N = 0.75, molar ratio of carbon and nitrogen elements in the influent water)

[0077]

[0078] Table 2 - Treatment results of the second low-carbon source sewage (C / N = 1.5, molar ratio of carbon and nitrogen elements in the influent water)

[0079]

[0080]

[0081] Table 3 - Treatment results of the third low-carbon source sewage (C / N = 2, molar ratio of carbon and nitrogen elements in the influent water)

[0082]

[0083] The above results show that after the device operates for 8 - 12 hours, the CODcr removal rate for low - carbon - source sewage exceeds 80%, and the CODcr concentration of the effluent reaches the national first - level discharge standard; the total removal rates of NH4 + -N and NO3 — -N both exceed 85%, and some are even close to 90%. The total nitrogen concentration of the effluent reaches the national first - level discharge standard; the total phosphorus removal rate reaches over 75%, and the total phosphorus concentration of the effluent reaches the national second - level discharge standard.

[0084] The above embodiments are only illustrative of the principles and effects of the present application and are not used to limit the present application. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present application should still be covered by the claims of the present application.

Claims

1. A low-carbon source sewage treatment device, characterized in that, Comprising: A box body (10) defining a box cavity (11); A cover member covering the upper opening of the box cavity (11); An anode assembly disposed in the box cavity (11) and configured to be connected to the positive electrode of a power source, the anode assembly including a first anode assembly (31), a second anode assembly (32), and a third anode assembly (33) arranged at intervals; A cathode assembly disposed in the box cavity (11) and configured to be connected to the negative electrode of a power source, the cathode assembly including a first cathode assembly (41), a second cathode assembly (42), and a third cathode assembly (43) arranged at intervals; An iron plate (20) disposed in the box cavity (11), the anode assembly being located between the iron plate (20) and the cathode assembly; Wherein, the first anode assembly (31), the second anode assembly (32), the third anode assembly (33), the first cathode assembly (41), the second cathode assembly (42), and the third cathode assembly (43) respectively include a first titanium mesh layer (401), a first porous fiber cotton layer (402), a first mixed filler layer (403), a second titanium mesh layer (404), a second mixed filler layer (405), a second porous fiber cotton layer (406), and a third titanium mesh layer (407) arranged in sequence, and the first mixed filler layer (403) and the second mixed filler layer (405) are mixtures of PHBV and short carbon fiber cuttings; The iron plate (20), the second anode assembly (32), the first cathode assembly (41), and the third cathode assembly (43) are in contact with the cover member and are spaced from the bottom wall (18) of the box body (10) by a first distance; the first anode assembly (31), the third anode assembly (33), and the second cathode assembly (42) are in contact with the bottom wall (18) of the box body (10) and are spaced from the cover member by a second distance, so that the water flow flows in an up-and-down folding direction.

2. The low-carbon source sewage treatment device according to claim 1, wherein The first titanium mesh layer (401), the second titanium mesh layer (404), and the third titanium mesh layer (407) are diamond-shaped titanium meshes; and / or The thicknesses of the first titanium mesh layer (401) and the third titanium mesh layer (407) are both greater than the thickness of the second titanium mesh layer (404); and / or The mesh sizes of the first titanium mesh layer (401) and the third titanium mesh layer (407) are both greater than the mesh size of the second titanium mesh layer (404).

3. The low-carbon source sewage treatment device according to claim 1, wherein The mass ratio of short carbon fiber cuttings to PHBV is 8:1 to 10:

1.

4. The low-carbon source sewage treatment device according to claim 1, characterized in that, The box body (10) has a left side wall (12) and a right side wall (13) arranged oppositely; an inlet (16) is provided at the upper part of the left side wall (12), and an outlet (17) is provided at the upper part of the right side wall (13).

5. The low-carbon source sewage treatment device according to claim 1, characterized in that, The box body (10) has a front side wall (15) and a rear side wall (14) arranged oppositely; the iron plate (20), the anode assembly, and the cathode assembly are respectively installed between the front side wall (15) and the rear side wall (14).

6. The low-carbon source sewage treatment device according to claim 5, characterized in that, A plurality of first fixing components are provided on the front side wall (15) and the rear side wall (14) to mount the first anode assembly (31), the third anode assembly (33) and the second cathode assembly (42). The first fixing component includes a first module (61) and a second module (62) arranged at intervals. The first anode assembly (31), the third anode assembly (33) and the second cathode assembly (42) are inserted between the corresponding first module (61) and second module (62). The lowermost first module and second module are in contact with the bottom wall (18). A plurality of the first fixing components and second fixing components are further provided on the front side wall (15) and the rear side wall (14) to mount the iron plate (20), the second anode assembly (32), the first cathode assembly (41), and the third cathode assembly (43). The second fixing component includes a third module (71), a fourth module (72) arranged at intervals, and a fifth module (73) located between the third module (71) and the fourth module (72). The iron plate (20), the second anode assembly (32), the first cathode assembly (41) and the third cathode assembly (43) are inserted between the corresponding third module (71) and fourth module (72) and are supported by the corresponding fifth module (73). The bottom of the fifth module (73) is spaced from the bottom wall (18) by the first distance.

7. The low-carbon source sewage treatment device according to claim 1, characterized in that, An anode region and a cathode region are formed in the box cavity (11). The iron plate (20) and the anode assembly are located in the anode region, and the cathode assembly is located in the cathode region. An aeration device is further provided in the anode region.

8. A low-carbon source sewage treatment method, characterized in that, Including: 1) Providing the low-carbon source sewage treatment device according to any one of claims 1-7; 2) Making the low-carbon source sewage enter the box cavity (11) from the water inlet (16), and the sewage water flow sequentially flows through the iron plate (20), the first anode assembly (31), the second anode assembly (32), the third anode assembly (33), the first cathode assembly (41), the second cathode assembly (42), and the third cathode assembly (43) in an up-and-down zigzag direction, and finally flows out from the water outlet (17).

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