A multi-stage ecological pig raising wastewater treatment system

Abstract

The present application relates to sewage treatment technical field, specifically to a kind of multi-stage ecological pig raising wastewater treatment system, comprising: anaerobic baffled reactor, it includes anaerobic baffled reaction pool;Anaerobic baffled reaction pool is equipped with multiple partition walls, and is divided into multiple independent anaerobic baffled reaction chamber, partition wall upper portion is equipped with water pipe, sewage flows in sequence between each anaerobic baffled reaction chamber by water pipe;Anaerobic baffled reaction pool bottom side is equipped with guide sludge inclined wall;Anaerobic baffled reaction pool water outlet below is equipped with sedimentation sludge inclined wall;Multi-stage countercurrent anaerobic biological filtration unit, and anaerobic baffled reaction pool is communicated;Including multiple filtration chambers filled with filler, each filtration chamber is sequentially communicated by high-low staggered water hole;Oxygenic ecological purification system, including intermediate water pool, part of intermediate water pool effluent is returned to anaerobic baffled reactor and microalgae purification pond.The present application is friendly to ecological environment, energy consumption is lower, drug dosage is less, operating cost is lower, and operation is simple.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically a multi-stage ecological pig farm wastewater treatment system. Background Technology

[0002] The current main process for treating pig farm wastewater is "pretreatment + anaerobic treatment + aerobic treatment + advanced treatment", namely "raw wastewater → bar screen → collection and mixing tank → solid-liquid separator → equalization tank → UASB → coagulation sedimentation → two-stage AO → secondary sedimentation tank → ozone disinfection → discharge meeting standards". This process is too complex, requires a lot of mechanical equipment, and has high energy consumption. It often requires the addition of a large amount of chemical agents, resulting in high operating costs per ton of water and low denitrification efficiency. At the same time, this process has poor shock resistance and load capacity. If it needs to be restarted for any reason, the previous debugging work needs to be repeated and the activated sludge needs to be re-cultivated.

[0003] The main reason for the above problems is that pig farm wastewater has a high content of suspended solids, good biodegradability, strong odor, and contains certain antibiotic residues. Pre-treatment at the front end, such as coarse and fine mechanical screens, solid-liquid separators, and air flotation, can remove most of the suspended solids and reduce the treatment pressure of subsequent processes. After pre-treatment, it enters anaerobic treatment, such as black membrane biogas digesters, IC anaerobic reactors, and UASB anaerobic reactors. As a high-concentration organic wastewater, pig farm wastewater can be converted into methane and carbon dioxide through the adsorption, absorption, and biodegradation of anaerobic microorganisms. However, IC and UASB anaerobic reactors are completely mixed, with bacterial colonies all mixed together, making them difficult to adjust and less resistant to shock loads, resulting in poor suspended solids removal capabilities. The effluent then enters the "aerobic treatment" stage, which removes residual organic matter. This "aerobic treatment" typically uses an AO + secondary sedimentation tank. To enhance nitrogen and phosphorus removal, sludge is recycled back to the preceding anaerobic zone from the secondary sedimentation tank. Therefore, the nitrogen removal efficiency is affected by the mixed liquor and sludge recycling ratio. Simultaneously, dissolved oxygen concentration needs to be controlled to prevent anaerobic or anoxic conditions in the secondary sedimentation tank, which could lead to polyphosphate accumulation. Phosphorus release or denitrification generates nitrogen, which affects sedimentation. The dissolved oxygen concentration should also not be too high to prevent the dissolved oxygen carried by the reflux liquid from affecting the anaerobic tank. During the operation and maintenance of the AO process, frequent microscopic examination and monitoring of relevant indicators are required to take timely corresponding measures. If the influent concentration does not meet the operating requirements of the AO process, additional carbon source or alkalinity needs to be added. If the ammonia nitrogen concentration in the influent is too high, it can easily lead to ammonia poisoning of microorganisms in the anaerobic and aerobic zones. Therefore, this process requires the operation and maintenance personnel to have certain relevant professional knowledge; otherwise, it can easily lead to process collapse and failure, making it impossible to operate normally.

[0004] To address the shortcomings of existing technologies, a multi-stage ecological pig farm wastewater treatment system is proposed to solve the aforementioned problems. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-stage ecological pig farm wastewater treatment system to solve the problems of existing processes being complex, having high civil engineering costs, weak resistance to shock loads, and the biochemical treatment section system being prone to collapse, requiring the monitoring of multiple indicators and demanding a high level of expertise from operation and maintenance personnel.

[0006] This invention is achieved through the following technical solution: A multi-stage ecological pig farm wastewater treatment system includes: An anaerobic baffled reactor includes an anaerobic baffled reaction tank with an inlet and an outlet on both sides. The anaerobic baffled reaction tank is divided into multiple independent anaerobic baffled reaction chambers by multiple partition walls. A water pipe is installed at the top of each partition wall, through which wastewater flows sequentially between the anaerobic baffled reaction chambers. Sludge guiding inclined walls are located on both sides of the bottom of each anaerobic baffled reaction chamber, and a first sludge discharge pipe is located at the bottom of each chamber. A sedimentation sludge inclined wall is located below the outlet in the anaerobic baffled reaction tank, and a biogas outlet is located at the top of each anaerobic baffled reaction chamber. A multi-stage counter-current anaerobic biological filtration unit has a water distribution port and a water discharge port on both sides, and the water distribution port is connected to the outlet of the anaerobic baffled reaction tank. The multi-stage counter-current anaerobic biological filtration unit includes multiple filtration chambers filled with fillers of different pore sizes. The fillers are used to remove particles of different sizes from the wastewater, while intercepting and fixing microorganisms to form corresponding stable biological colonies. The filtration chambers are connected to each other through water passages arranged at different heights. A second row of sludge pipes is provided in the filtration chamber below the fillers. The aerobic ecological purification system includes a microalgae purification tank, a primary non-powered aerobic artificial soil ecological purification unit, and an intermediate water tank connected in sequence. The microalgae purification tank is connected to the drain outlet of the multi-stage counter-current anaerobic biological filtration unit. Part of the effluent from the intermediate water tank is returned to the anaerobic baffle reactor and the microalgae purification tank, while the remaining effluent is used for subsequent processes.

[0007] Optionally, the anaerobic baffle reaction chamber is provided with six chambers, the volume of which decreases sequentially along the sewage flow direction; the filtration chamber is provided with six chambers, the packing materials of which are sequentially arranged along the sewage flow direction as multi-faceted hollow sphere packing, brush filter media, coarse ceramsite, 13 stone, fine ceramsite and 05 stone.

[0008] Optionally, the water passages are arranged sequentially along the sewage flow direction, with odd-numbered water passages located at lower positions and even-numbered water passages located at higher positions. The heights of the water distribution outlet and the drain outlet correspond to the heights of the water passages located at higher positions. The water passages located at lower positions have their inlet ends connected to a water collection blind pipe, as do the water passages located at higher positions and the drain outlet located within the anaerobic baffle reaction tank. The water passages located at higher positions have their outlet ends connected to a water distribution blind pipe, as do the water distribution outlet located within the anaerobic baffle reaction tank.

[0009] Optionally, a first overflow weir is provided on the inner wall of the anaerobic baffle reaction tank at the outlet, and a second overflow weir is provided on the inner wall of the multi-stage countercurrent anaerobic biological filtration unit at the drain outlet. The second overflow weir has a water collection hole that connects to the blind water collection pipe in the corresponding filtration chamber. A water distribution trough is provided on the outer wall of the multi-stage countercurrent anaerobic biological filtration unit at the water distribution port.

[0010] Optionally, the primary non-powered aerobic artificial soil ecological purification unit includes, from top to bottom, an artificial soil layer, at least two biological filter layers, and a water collection and drainage layer. A breathing and ventilation layer is provided between two adjacent biological filter layers. The breathing and ventilation layer is used to draw out the gas in the primary non-powered aerobic artificial soil ecological purification unit and draw in outside air to complete gas exchange. A water distribution pipe is arranged on the artificial soil layer, and a water collection and drainage pipe is arranged in the water collection and drainage layer. The water distribution pipe of the primary non-powered aerobic artificial soil ecological purification unit is connected to the microalgae purification pool, and the water collection and drainage pipe of the primary non-powered aerobic artificial soil ecological purification unit is connected to the intermediate water pool.

[0011] Optionally, a transition layer is provided between the biofilter layer and the breathing and ventilation layer; the breathing and ventilation layer is provided with breathing and ventilation pipes that connect to the ground surface.

[0012] Optionally, the aerobic ecological purification system further includes a second-stage non-powered aerobic artificial soil ecological purification unit. The remaining effluent from the intermediate water tank is connected to the second-stage non-powered aerobic artificial soil ecological purification unit, and is treated by the second-stage non-powered aerobic artificial soil ecological purification unit to meet the standards before being discharged.

[0013] Optionally, it also includes an equalization tank, two-stage mechanical bar screens, a mixing tank, and a fecal sludge solid-liquid separator. The equalization tank is connected to the raw wastewater, the two-stage mechanical bar screens are connected to the equalization tank and the mixing tank respectively, and the fecal sludge solid-liquid separator is connected to the mixing tank and the anaerobic baffled reactor respectively.

[0014] Optionally, it also includes a sludge tank, a sludge thickening tank, and a screw press. The first sludge discharge pipe and the second sludge discharge pipe are both connected to the sludge tank. The sludge tank, the sludge thickening tank, and the screw press are connected in sequence. The supernatant separated by the screw press enters the mixing tank.

[0015] Compared with the prior art, the present invention provides a multi-stage ecological pig farm wastewater treatment system with the following advantages: the anaerobic baffled reaction tank, multi-stage countercurrent anaerobic biological filtration unit and aerobic ecological purification system set up in the present invention are environmentally friendly, have low energy consumption, low dosage of medicine, low operating cost, simple operation, high reliability of automatic operation, low technical requirements for operators, easy system start-up, short commissioning cycle and no odor. Attached Figure Description

[0016] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a schematic diagram of the anaerobic baffled reactor in this invention; Figure 3 This is a schematic diagram of the structure of the multi-stage countercurrent anaerobic biological filtration unit in this invention; Figure 4 This is a schematic diagram of the first and second stage non-powered aerobic artificial soil ecological purification units in this invention.

[0017] In the diagram: 10. Anaerobic baffled reactor; 11. Anaerobic baffled reaction tank; 110. Inlet; 111. Outlet; 12. Partition wall; 13. Anaerobic baffled reaction chamber; 14. Water pipe; 15. Sludge guide inclined wall; 16. First sludge discharge pipe; 17. Settling sludge inclined wall; 18. First overflow weir; 19. Biogas outlet; 20. Multi-stage counter-current anaerobic biological filtration unit; 21. Filtration chamber; 210. Water distribution port; 211. Drainage outlet; 212. Water distribution trough; 213. Second overflow weir; 22. Packing material; 23. 24. Water passage hole; 25. Water collection blind pipe; 26. Water distribution blind pipe; 37. Second mud discharge pipe; 38. Aerobic ecological purification system; 39. Microalgae purification pond; 30. Primary non-powered aerobic artificial soil ecological purification unit; 31. Artificial soil layer; 32. Biological filter layer; 32. Breathing and ventilation layer; 32. Transition layer; 32. Water collection and drainage layer; 32. Water distribution pipe; 32. Breathing and ventilation pipe; 32. Water collection and drainage pipe; 33. Intermediate water tank; 34. Second-stage non-powered aerobic artificial soil ecological purification unit. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example: Please refer to Figures 1 to 4As shown, according to an embodiment of the present invention, a technical solution is provided: a multi-stage ecological pig farm wastewater treatment system, comprising a pretreatment device, an anaerobic baffled reactor 10, a multi-stage countercurrent anaerobic biological filtration unit 20, and an aerobic ecological purification system 30 connected in sequence. Wherein: The pretreatment equipment includes an equalization tank, a two-stage rotary mechanical bar screen, a mixing tank, and a manure solid-liquid separator connected in sequence. The equalization tank is connected to the raw water of pig farm wastewater.

[0020] The anaerobic baffle reactor 10 includes an anaerobic baffle reaction tank 11, which can be constructed of semi-underground reinforced concrete with appropriate anti-corrosion treatment on its inner walls to enhance its insulation and corrosion resistance. The anaerobic baffle reaction tank 11 has an inlet 110 and an outlet 111 on both sides, with the inlet 110 connected to a fecal solid-liquid separator. The anaerobic baffle reaction tank 11 has five partition walls 12, dividing it into six independent anaerobic baffle reaction chambers 13. Because the influent concentration of wastewater is higher than its effluent concentration, the upstream anaerobic baffle reaction chamber 13 bears a greater local load. Therefore, the volume of the six anaerobic baffle reaction chambers 13 decreases sequentially along the wastewater flow direction, especially the first anaerobic baffle reaction chamber 13, whose volume is significantly smaller. A water pipe 14 is installed above the partition wall 12, through which wastewater flows sequentially between the anaerobic baffle reaction chambers 13. The anaerobic baffle reaction chamber 13 has sludge guiding inclined walls 15 on both sides of its bottom, and a first sludge discharge pipe 16 at its bottom. The anaerobic baffle reaction tank 11 has a settling sludge inclined wall 17 located below the outlet 111. The sludge guiding inclined walls 15 and the settling sludge inclined wall 17 allow sludge to settle better at the bottom of the tank, preventing sludge overflow. When treating high-concentration pig farm wastewater, a large amount of biogas is generated. The rising biogas can promote the mixing of wastewater and sludge; therefore, a biogas outlet 19 is provided at the top of each anaerobic baffle reaction chamber 13, which can be connected to an external biogas collection system.

[0021] The multi-stage counter-current anaerobic biological filtration unit 20 has a water distribution port 210 and a drainage port 211 on both sides, respectively. The water distribution port 210 is connected to the outlet 111 of the anaerobic baffled reaction tank 11. The multi-stage counter-current anaerobic biological filtration unit 20 includes six filtration chambers 21, each filled with packing material 22 of different pore sizes. The particle size of the packing material 22 in the six filtration chambers 21 gradually decreases along the direction of sewage flow. Specifically, it can be set as multi-faceted hollow ball packing material, brush filter media, coarse ceramsite, 13 stone, fine ceramsite, and 0.5 stone in sequence. The packing material 22 is used to remove particles of different sizes in sewage, while intercepting and fixing microorganisms to form corresponding stable biological colonies. The six filtration chambers 21 The anaerobic baffle reaction tank 11 is connected by five water passages 23 arranged at different heights. The five water passages 23 are arranged in sequence along the direction of sewage flow. The water passages 23 with odd numbers are located at lower positions, and the water passages 23 with even numbers are located at higher positions. The heights of the water distribution port 210 and the drain port 211 correspond to the water passages 23 located at higher positions. The water passages 23 located at lower positions, the water passages 23 located at higher positions, and the drain port 211 located at one end in the anaerobic baffle reaction tank 11 are all connected to a water collection blind pipe 24. The water passages 23 located at higher positions and the water distribution port 210 located at one end in the anaerobic baffle reaction tank 11 are all connected to a water distribution blind pipe 25. The lower part of the filter chamber 21 is fixedly connected with a horizontally arranged fiberglass grating for supporting each packing 22. The bottom of the fiberglass grating is supported by vertically distributed galvanized channel steel. A second row of mud pipes 26 is provided in the filter chamber 21 below the packing 22 and next to the galvanized channel steel.

[0022] The aerobic ecological purification system 30 includes a microalgae purification pool 31, a primary non-powered aerobic artificial soil ecological purification unit 32, and an intermediate water pool 33 connected in sequence. The primary non-powered aerobic artificial soil ecological purification unit 32 includes an artificial soil layer 321, at least two biological filter layers 322, and a water collection and drainage layer 325 laid in sequence from top to bottom. A breathing and ventilation layer 323 is provided between two adjacent biological filter layers 322. The breathing and ventilation layer 323 is used to draw out the gas in the primary non-powered aerobic artificial soil ecological purification unit 32 and draw in the outside air to complete the gas exchange. A breathing and ventilation pipe 327 connected to the ground surface is arranged in the breathing and ventilation layer 323. A transition layer 324 is provided between the biological filter layer 322 and the breathing and ventilation layer 323. The artificial soil layer 321 is mostly composed of medium or coarse sand. This layer contains a large number of ultramicro soil microorganisms, such as bacteria, archaea, and fungi, which are unique to aerobic soil environments. Adaptable landscape plants or economic crops can be planted in the artificial soil layer 321. Water distribution pipes 326 are installed on the artificial soil layer 321. The biological filter layer 322 and the aeration layer 323 can be increased or decreased according to water quality and quantity requirements. The biological filter layer 322 is composed of small-particle-size pure quartz sand or pure manufactured sand, or a mixture of the former two with carbon powder (granules) in a certain proportion to form the matrix filter media. The aeration layer 323 is physically layered using coarse crushed stone or coarse gravel. The water collection and drainage layer 325 is filled with larger-particle-size filler. Water collection and drainage pipes 328 are installed in the water collection and drainage layer 325, through which treated water is discharged. The primary non-powered aerobic artificial soil ecological purification unit 32 uses intermittent water intake to ensure oxygenation. The overall environment is aerobic, while the microenvironment is hypoxic and anaerobic.

[0023] The microalgae purification tank 31 is connected to the drain outlet 211 of the multi-stage counter-current anaerobic biological filtration unit 20. Part of the effluent from the intermediate water tank 33 is returned to the anaerobic baffle reactor 10 and the microalgae purification tank 31, while the remaining effluent is used for subsequent processes.

[0024] The multi-stage ecological pig farm wastewater treatment system also includes a sludge tank, a sludge thickening tank, and a screw press. The first sludge pipe 16 and the second sludge pipe 26 are both connected to the sludge tank. The sludge tank, the sludge thickening tank, and the screw press are connected in sequence. The supernatant separated by the screw press enters the mixing tank, and the sludge cake generated by the screw press is handed over to a qualified unit for treatment.

[0025] Based on the above embodiments, a first overflow weir 18 is provided on the inner wall of the anaerobic baffled reactor 11 at the outlet 111, and a second overflow weir 213 is provided on the inner wall of the multi-stage countercurrent anaerobic biological filtration unit 20 at the drain outlet 211. The second overflow weir 213 has a water collection hole that connects to the water collection blind pipe 24 in the corresponding filtration chamber 21. A water distribution trough 212 is provided on the outer wall of the multi-stage countercurrent anaerobic biological filtration unit 20 at the water distribution port 210.

[0026] Based on the above embodiments, the aerobic ecological purification system 30 further includes a second-stage non-powered aerobic artificial soil ecological purification unit 34, the structure of which is set with reference to the primary non-powered aerobic artificial soil ecological purification unit 32. Part of the effluent from the intermediate pool 33 is connected to the anaerobic baffle reactor 10 and the microalgae purification pool 31 through a diversion pipe for further denitrification. A portion of the effluent is pumped back to the inlet 110 of the anaerobic baffle reactor 10 and the microalgae purification pool 31. The remaining effluent is connected to the second-stage non-powered aerobic artificial soil ecological purification unit 34, and finally treated by the second-stage non-powered aerobic artificial soil ecological purification unit 34 to meet the standards before being discharged.

[0027] It should be noted that the wastewater first enters the equalization tank, where alkaline solution is added to adjust its pH value. Then, the wastewater in the equalization tank is pumped into a two-stage rotary mechanical screen to remove large suspended solids such as pig hair and epidemic prevention waste. After that, the wastewater enters the mixing tank, which is equipped with a mixer. The mixer mixes the feces and wastewater evenly before pumping it into a fecal sludge solid-liquid separator. The separated fecal sludge can be processed into organic fertilizer and is generally transported off-site for resource utilization.

[0028] After solid-liquid separation, the wastewater flows by gravity to the anaerobic baffle reactor 10. The anaerobic baffle reactor 10 utilizes anaerobic bacteria to perform anaerobic digestion of high-concentration aquaculture wastewater, causing organic matter to undergo hydrolysis, acidification, and methanation stages, converting it into methane, carbon dioxide, water, hydrogen sulfide, and ammonia. Six anaerobic baffle reactor chambers 13 are connected in series in the direction of wastewater flow, operating independently. Each chamber allows for the cultivation and adaptation of suitable microbial communities, while preventing backmixing and reducing sludge bulking. Multiple water pipes 14 are installed on the partition wall 12. As wastewater enters the next anaerobic baffle reactor chamber 13 through these pipes, it impacts the sludge deposited at the bottom from top to bottom, and this process is repeated. To prevent excessive acidification in the first anaerobic baffle reactor chamber 13, a sodium bicarbonate dosing pipeline can be installed. To enhance phosphorus removal, a phosphorus removal agent dosing pipeline can be installed in the sixth anaerobic baffle reactor chamber 13 for periodic dosing.

[0029] The anaerobic baffled reactor 10 has a simple structure, low cost, low energy consumption, high volume utilization rate, good hydraulic conditions, strong resistance to shock loads, low sludge bed expansion, and good tolerance to toxic and harmful substances in the influent.

[0030] After passing through the anaerobic baffled reactor 10, the wastewater flows by gravity to the multi-stage countercurrent anaerobic biological filtration unit 20, where it flows in an S-shape between the filtration chambers 21. The multi-stage countercurrent anaerobic biological filtration unit 20 uses packing material 22 to filter out fine suspended solids and degrade some organic pollutants. By arranging packing material 22 with varying pore sizes, suspended solids can be intercepted. Simultaneously, a large number of bacterial flocs adhere to the packing material 22, which can degrade some pollutants. Through the division of the tank, each unit can independently cultivate a dominant bacterial community. The packing material inside the tank helps to retain the same microorganisms, forming stable biological colonies, thus ensuring the stable operation of the system. This unit also has excellent SS removal capacity, is not prone to forming stagnant zones, is easy to start up and debug, has high resistance to shock loads, and can effectively remove COD, achieve anaerobic ammonia oxidation, and short-cut nitrification.

[0031] After being treated by a multi-stage counter-current anaerobic biological filtration unit 20, the wastewater flows by gravity into a microalgae purification tank 31. The tank is planted with algae such as Chlorella and diatoms, which absorb organic carbon sources, remove nitrogen and phosphorus, and metabolize organic pollutants from the wastewater. A lift pump is installed in the microalgae purification tank 31 to periodically pump the wastewater into the distribution pipe 326 of the primary non-powered aerobic artificial soil ecological purification unit 32. The effluent from the primary non-powered aerobic artificial soil ecological purification unit 32 is discharged to the intermediate water tank 33 through the collection and drainage pipe 328. From the intermediate water tank 33, a portion of the effluent is returned to the anaerobic baffle reactor 10 and the microalgae purification tank 31 via a lift pump. The remaining effluent is pumped to the second-stage non-powered aerobic artificial soil ecological purification unit 34, where it is finally treated to meet standards and discharged. The primary and secondary non-powered aerobic artificial soil ecological purification units 32 and 34 effectively degrade and purify organic pollutants in wastewater through a large number of microbial communities in the artificial soil layer, further purifying and removing suspended solids, nitrogen, and phosphorus from the wastewater. Simultaneously, the biofilter layer 322 and the adsorption and interception effects of the water-purifying plant roots prevent the loss of microorganisms and effectively acclimate specific bacterial communities.

[0032] The primary and secondary non-powered aerobic artificial soil ecological purification units 32 and 34 do not require additional power for oxygen supply. They utilize the respiration effect generated by the internal and external pressure difference during hydraulic infiltration to supply oxygen to the microorganisms in the internal packing matrix. These units do not produce residual activated sludge and do not generate secondary pollution such as noise or odor. They have low operation and maintenance costs, require no blowers or chemical additives, and can be used to cultivate landscape plants, creating park or courtyard-style water purification modules, as well as to grow economically beneficial plants that can be harvested after maturity. The units are easy to operate, requiring no control of the carbon-nitrogen ratio of the influent or detection of microbial concentrations. They lack complex mechanical equipment, allowing even ordinary workers to operate and maintain them. The packing matrix contains abundant microbial communities that can biologically inhibit harmful bacteria and eliminate harmful bacteria in the wastewater. The effluent quality is stable and resistant to fluctuations in water quality and quantity. If the unit is temporarily shut down, it can be quickly restarted.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-stage ecological pig farm wastewater treatment system, characterized in that, include: An anaerobic baffled reactor (10) includes an anaerobic baffled reaction tank (11), with an inlet (110) and an outlet (111) on both sides of the anaerobic baffled reaction tank (11); the anaerobic baffled reaction tank (11) is provided with multiple partition walls (12), which divide the anaerobic baffled reaction tank (11) into multiple independent anaerobic baffled reaction chambers (13); and a water pipe (14) is provided on the upper part of the partition wall (12). Wastewater flows sequentially between the anaerobic baffle reaction chambers (13) through the water pipe (14); the bottom of the anaerobic baffle reaction chamber (13) is provided with sludge guiding inclined walls (15) on both sides, and the bottom of the anaerobic baffle reaction chamber (13) is provided with a first sludge discharge pipe (16); the anaerobic baffle reaction tank (11) is provided with a sedimentation sludge inclined wall (17) below the water outlet (111), and each anaerobic baffle reaction chamber (13) is provided with a biogas outlet (19) at the top; A multi-stage countercurrent anaerobic biological filtration unit (20) is provided with a water distribution port (210) and a drain outlet (211) on both sides. The water distribution port (210) is connected to the outlet (111) of the anaerobic baffled reaction tank (11). The multi-stage countercurrent anaerobic biological filtration unit (20) includes multiple filtration chambers (21) filled with fillers (22) of different pore sizes. The fillers (22) are used to remove particles of different sizes in sewage, while intercepting and fixing microorganisms to form corresponding stable biological colonies. Each filtration chamber (21) is connected to the others by water passage holes (23) arranged at different heights. A second sludge pipe (26) is provided in the filtration chamber (21) below the fillers (22). The aerobic ecological purification system (30) includes a microalgae purification tank (31), a primary non-powered aerobic artificial soil ecological purification unit (32), and an intermediate water tank (33) connected in sequence; the microalgae purification tank (31) is connected to the drain outlet (211) of the multi-stage countercurrent anaerobic biological filtration unit (20), and part of the effluent from the intermediate water tank (33) is returned to the anaerobic baffle reactor (10) and the microalgae purification tank (31), while the remaining effluent is used for subsequent processes; The primary non-powered aerobic artificial soil ecological purification unit (32) includes an artificial soil layer (321), at least two biological filter layers (322), and a water collection and drainage layer (325) laid from top to bottom. A breathing and ventilation layer (323) is provided between two adjacent biological filter layers (322). The breathing and ventilation layer (323) is used to draw out the gas in the primary non-powered aerobic artificial soil ecological purification unit (32) and draw in the outside air to complete the gas exchange. A water distribution pipe (326) is arranged on the artificial soil layer (321), and a water collection and drainage pipe (328) is arranged in the water collection and drainage layer (325). The water distribution pipe (326) of the primary non-powered aerobic artificial soil ecological purification unit (32) is connected to the microalgae purification pool (31), and the water collection and drainage pipe (328) of the primary non-powered aerobic artificial soil ecological purification unit (32) is connected to the intermediate water pool (33).

2. The multi-stage ecological pig farm wastewater treatment system according to claim 1, characterized in that, The anaerobic baffle reaction chamber (13) is provided in six parts, and the volume of the six anaerobic baffle reaction chambers (13) decreases sequentially along the sewage flow direction; the filter chamber (21) is provided in six parts, and the packing material (22) in the six filter chambers (21) is sequentially set as multi-faceted hollow ball packing, brush filter material, coarse ceramsite, 13 stone, fine ceramsite and 05 stone along the sewage flow direction.

3. The multi-stage ecological pig farm wastewater treatment system according to claim 1, characterized in that, The water passages (23) are arranged sequentially along the direction of sewage flow. The water passages (23) with odd numbers are set at lower positions, and the water passages (23) with even numbers are set at higher positions. The heights of the water distribution port (210) and the drain port (211) correspond to the water passages (23) located at higher positions. The water inlet end of the water passage (23) located at lower positions, the water inlet end of the water passage (23) located at higher positions, and the end of the drain port (211) located in the anaerobic baffle reaction tank (11) are all connected to a water collection blind pipe (24). The water outlet end of the water passage (23) located at higher positions and the end of the water distribution port (210) located in the anaerobic baffle reaction tank (11) are all connected to a water distribution blind pipe (25).

4. The multi-stage ecological pig farm wastewater treatment system according to claim 1, characterized in that, The anaerobic baffled reaction tank (11) has a first overflow weir (18) on its inner wall at the outlet (111), and the multi-stage countercurrent anaerobic biological filtration unit (20) has a second overflow weir (213) on its inner wall at the drain outlet (211). The second overflow weir (213) has a water collection hole that connects to the water collection blind pipe (24) in the corresponding filtration chamber (21). The multi-stage countercurrent anaerobic biological filtration unit (20) has a water distribution trough (212) on its outer wall at the water distribution outlet (210).

5. The multi-stage ecological pig farm wastewater treatment system according to claim 1, characterized in that, A transition layer (324) is provided between the biofilter layer (322) and the breathing and ventilation layer (323); the breathing and ventilation layer (323) is provided with breathing and ventilation pipes (327) that connect to the ground surface.

6. The multi-stage ecological pig farm wastewater treatment system according to claim 1, characterized in that, The aerobic ecological purification system (30) also includes a second-stage non-powered aerobic artificial soil ecological purification unit (34). The remaining effluent from the intermediate water tank (33) is connected to the second-stage non-powered aerobic artificial soil ecological purification unit (34), and is treated by the second-stage non-powered aerobic artificial soil ecological purification unit (34) to meet the standards before being discharged.

7. The multi-stage ecological pig farm wastewater treatment system according to claim 1, characterized in that, It also includes an equalization tank, two-stage mechanical bar screens, a mixing tank, and a fecal sludge solid-liquid separator. The equalization tank is connected to the raw wastewater, the two-stage mechanical bar screens are connected to the equalization tank and the mixing tank respectively, and the fecal sludge solid-liquid separator is connected to the mixing tank and the anaerobic baffled reactor (10) respectively.

8. The multi-stage ecological pig farm wastewater treatment system according to claim 7, characterized in that, It also includes a sludge tank, a sludge thickening tank and a screw press. The first sludge discharge pipe (16) and the second sludge discharge pipe (26) are both connected to the sludge tank. The sludge tank, the sludge thickening tank and the screw press are connected in sequence. The supernatant separated by the screw press enters the mixing tank.

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