Aquaculture wastewater treatment system

Abstract

This application discloses an aquaculture wastewater treatment system, relating to the technical field of wastewater treatment. The system includes an equalization tank, a flotation unit, a biofilm tank, a sludge tank, and a dewatering unit. The equalization tank is used to homogenize the quality and quantity of the aquaculture wastewater, and its bottom is connected to the flotation unit via a pipe. A pipe is connected between the flotation unit and the biofilm tank for transporting the aquaculture wastewater after flotation, and a pipe is connected between the flotation unit and the sludge tank for transporting the flotated sludge. A pipe is connected between the biofilm tank and the sludge tank for transporting the aged biofilm. A pipe is connected between the sludge tank and the dewatering unit for transporting sludge, and the dewatered liquid obtained from the dewatering unit can be returned to the equalization tank. This application can effectively improve the treatment effect of aquaculture wastewater, thereby effectively reducing the environmental pollution caused by aquaculture wastewater discharge.

Description

Technical Field

[0001] This application relates to the technical field of wastewater treatment, and in particular to an aquaculture tailwater treatment system. Background Technology

[0002] Aquaculture wastewater is the water discharged during the aquaculture process that has changed in quality due to factors such as the metabolism of farmed animals, feed residues, drug use, and various biological activities in the water.

[0003] Currently, the wastewater generated during aquaculture (such as eel farming) contains large amounts of organic matter and pollutants such as nitrogen and phosphorus. Phosphorus is mainly found in suspended solids such as excrement and leftover feed, while nitrogen is mainly nitrate nitrogen and a small amount of ammonia nitrogen. Therefore, if aquaculture wastewater is discharged directly without treatment, it will pollute the surrounding environment.

[0004] Traditionally, aquaculture wastewater is treated through sedimentation and filtration. During the treatment process, residual feed and excrement in the wastewater are settled (sedimentation tank) and filtered (such as by filter dams or biofilm treatment). The filtered wastewater is then discharged directly.

[0005] However, even after traditional treatment methods, aquaculture wastewater typically still contains high levels of organic matter and pollutants such as nitrogen and phosphorus. Furthermore, the pollutant concentration in wastewater from factory-scale aquaculture is even higher. Since 2023, various regions across China have issued their own "Aquaculture Wastewater Discharge Standards," requiring that effluent COD, total nitrogen, and total phosphorus levels typically be below 10 mg / L, 3 mg / L, and 0.5 mg / L, respectively. Therefore, there is an urgent need for an aquaculture wastewater treatment system with better treatment efficiency. Summary of the Invention

[0006] This application provides an aquaculture wastewater treatment system that can effectively improve the treatment effect of aquaculture wastewater, thereby effectively reducing the pollution of the environment caused by aquaculture wastewater discharge.

[0007] This application provides an aquaculture wastewater treatment system, which adopts the following technical solution:

[0008] An aquaculture wastewater treatment system includes an equalization tank, an air flotation device, a biofilm tank, a sludge tank, and a dewatering device;

[0009] The equalization tank is used to equalize the quality and quantity of aquaculture wastewater, and the bottom of the equalization tank is connected to the air flotation equipment via a pipe.

[0010] The air flotation equipment is connected to the biofilm tank by a pipeline for conveying the aquaculture wastewater after air flotation, and the air flotation equipment is connected to the sludge tank by a pipeline for conveying the air flotation sludge.

[0011] A pipe for transporting aged biofilm is connected between the biofilm tank and the sludge tank; a pipe for transporting sludge is connected between the sludge tank and the dewatering equipment, and the dewatered liquid obtained by the dewatering equipment can be sent back to the equalization tank.

[0012] By adopting the above technical solution, after the aquaculture wastewater is allowed to settle, the wastewater with high pollutant concentration is treated by air flotation to remove most of the suspended solids and total phosphorus and other pollutants. The wastewater is then treated in a biofilm tank to remove organic matter, ammonia nitrogen, total nitrogen and total phosphorus and other pollutants. Furthermore, the air flotation sludge and biofilm are treated together in a sludge tank, and then dewatered by a dewatering device to obtain sludge cake and dewatered clear liquid. The dewatered clear liquid can be sent back to the equalization tank to continue participating in the aquaculture wastewater treatment. This can effectively improve the treatment effect of aquaculture wastewater, and at the same time, it can properly treat the substances obtained after the aquaculture wastewater treatment, thereby effectively reducing the pollution of the environment caused by the discharge of aquaculture wastewater.

[0013] Optionally, the biofilm tank includes a primary A1 tank, a primary A2 tank, a primary O tank, a secondary A tank, and a secondary O tank arranged sequentially along the sewage flow direction, and each tank is equipped with packing material for microbial attachment and growth.

[0014] The bottom of the primary A1 pool and the primary A2 pool has a first connecting port, the top of the primary A2 pool and the primary O pool has a first overflow port, the bottom of the primary O pool and the secondary A pool has a second connecting port, and the top of the secondary A pool and the secondary O pool has a second overflow port.

[0015] Both the primary O-tank and the secondary O-tank are equipped with aeration devices.

[0016] By adopting the above technical solution, microorganisms can attach and grow on the packing material to form a biofilm and remain in their respective tanks, effectively reducing the probability of microorganisms flowing to the next tank with the sewage. This effectively ensures the species differentiation of microorganisms in the aerobic and anoxic tanks and makes the proportion of effective dominant microbial species in each tank high, thereby significantly improving the nitrification performance of the O tank and the denitrification capacity of the A tank, and further improving the treatment effect of sewage in the biofilm tank.

[0017] Optionally, a sludge removal device is provided in each of the primary A1 tank, the primary A2 tank, the primary O tank, the secondary A tank, and the secondary O tank;

[0018] The sludge removal device includes a sludge suction device and a baffle plate; the sludge suction device includes a sludge suction pipe and a sludge suction pump; one end of the sludge suction pipe is connected to the sludge tank and located in a corner of the tank, and the other end is immersed in the liquid and close to the liquid surface; the sludge suction pump is installed on the sludge suction pipe and can drive the biofilm located on the liquid surface in the tank to be sent into the sludge tank through the sludge suction pipe.

[0019] The mudguard is installed in the pool, with part of the mudguard above the liquid surface and part of it immersed in the liquid, and located on one side of the end of the suction pipe along the direction of sewage flow in the pool.

[0020] By adopting the above technical solution, the sludge removal device can promptly discharge the aged biofilm that has detached from the packing material, thereby effectively improving the purity of the wastewater in the biofilm tank, and further improving the water quality obtained after the wastewater is treated by the biofilm tank.

[0021] Optionally, the sludge suction device may also include a movable tube and a floating component;

[0022] The movable tube is movably connected to the end of the sludge suction tube in the pool. The movable tube moves vertically and remains in communication with the sludge suction tube during its movement.

[0023] The top of the active tube has a sludge suction port, and the floating component is disposed on the top of the active tube; the floating component floats on the liquid surface, so that the position of the sludge suction port is kept no higher than the liquid surface, and the biofilm floating on the liquid surface can enter the sludge suction port.

[0024] By adopting the above technical solution, the sludge suction device can easily remove sludge from the biofilm floating on the liquid surface according to the liquid level in the pool. At the same time, it can reduce the amount of liquid discharged through the sludge suction device along with the sludge, thereby effectively improving the sludge suction effect of the sludge suction device.

[0025] Optionally, the mudguard is provided with a plurality of filter holes for filtering biofilm.

[0026] By adopting the above technical solution, the mudguard can both intercept biofilm and reduce its impact on the flow of sewage in the pool.

[0027] Optionally, the mudguard has an arc-shaped plate structure, and the axis of the arc trajectory of the mudguard is vertical.

[0028] By adopting the above technical solution, the arc-shaped concave space of the mudguard can provide a larger retention space for the biofilm it intercepts, thereby effectively improving the mudguard's interception effect on biofilm.

[0029] Optionally, the filter holes are constricted in the direction of approaching the suction pipe.

[0030] By adopting the above technical solution, during the operation of the sludge suction device, the sewage in the pool can be affected by it and flow through the filter holes, thereby effectively driving the biofilm intercepted by the baffle plate to move towards the sludge suction port. At the same time, it can clear the filter holes and reduce the probability of the biofilm clogging the filter holes.

[0031] Optionally, the sludge removal device may also include a driving component;

[0032] One end of the arc-shaped trajectory of the mudguard is rotatably connected to the pool body, and the rotation axis of the mudguard is vertical; the driving component is disposed on the pool body and can drive the mudguard to rotate.

[0033] When the mudguard is rotated to its limit position in a direction away from the suction pipe, the pool wall on the side of the mudguard and the suction pipe away from the mudguard will be flared out along the direction of sewage flow in the pool.

[0034] When the mudguard is rotated to its limit position in the direction of the suction pipe, the pool wall on the side of the mudguard and the suction pipe away from the mudguard forms a narrowing shape along the direction of sewage flow in the pool.

[0035] By adopting the above technical solution, when the sludge suction device is not running, the baffle plate mainly intercepts the biofilm, and the interception area around the suction port for the biofilm to stay is relatively large; when the sludge suction device is running, the rotation of the baffle plate can gather the biofilm it intercepts, making it easier for the biofilm to be discharged through the sludge suction device.

[0036] Optionally, each of the primary A1 pool, the primary A2 pool, and the secondary A pool is equipped with a plurality of flow promoters;

[0037] The flow promoter is located near the bottom of the pool, and several of the flow promoters are capable of driving the wastewater to flow in a circular trajectory within the pool.

[0038] By adopting the above technical solution, the flow promoter can promote the flow of sewage in the pool, thereby promoting the contact between sewage and microorganisms on the packing material, and further improving the sewage treatment effect of the biofilm pool.

[0039] Optionally, the primary A1 pool is further provided with several guide plates, and the several guide plates are separated in the pool to form several flow channels.

[0040] By adopting the above technical solution, the intensity of the sewage flow entering the biofilm tank can be further increased, the efficiency of the sewage-microorganism reaction can be further improved, and the probability of pollutants in the sewage settling and accumulating in the first tank, which would affect the overall sewage treatment effect of the biofilm tank, can be reduced.

[0041] In summary, this application includes at least one of the following beneficial effects:

[0042] 1. It can effectively improve the treatment effect of aquaculture wastewater and properly treat the substances obtained after the aquaculture wastewater treatment, thereby effectively reducing the pollution of the environment caused by the discharge of aquaculture wastewater.

[0043] 2. It can effectively ensure the species differentiation of microorganisms in aerobic and anoxic tanks, thereby improving the treatment effect of biofilm tank on sewage, and further improving the overall treatment effect of the treatment system on aquaculture wastewater.

[0044] 3. It can improve the effect of the sludge removal device in removing biofilm that has detached from the packing material in the biofilm tank, thereby effectively improving the water quality obtained after the wastewater is treated by the biofilm tank;

[0045] 4. It can improve the efficiency of the sludge removal device in removing biofilm that has detached from the packing material in the biofilm tank, and reduce the probability of sewage being discharged along with the biofilm. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of an aquaculture wastewater treatment system according to Example 1;

[0047] Figure 2 This is a partial structural diagram of the biofilm tanks arranged along a straight trajectory in Example 1 (with the guide plate omitted).

[0048] Figure 3 This is a partial structural diagram of the biofilm tanks arranged along a straight trajectory in Example 1 (filler omitted);

[0049] Figure 4 This is a partial structural schematic diagram of the sludge removal device in Example 1;

[0050] Figure 5 This is a partial structural schematic diagram of the sludge removal device in Example 2;

[0051] Figure 6 This is a partial cross-sectional view of the sludge suction device in Example 2;

[0052] Figure 7 This is a partial cross-sectional view of the sludge removal device in Example 2 when sludge removal is not performed;

[0053] Figure 8 This is a partial cross-sectional view of the sludge removal device in Example 2 during sludge removal.

[0054] Explanation of reference numerals in the attached drawings: 1. Equalization tank; 2. Air flotation equipment; 3. Biofilm tank; 31. Primary A1 tank; 32. Primary A2 tank; 33. Primary O tank; 34. Secondary A tank; 35. Secondary O tank; 36. Flow promoter; 37. Guide plate; 38. Packing material; 39. Aeration device; 4. Sludge tank; 5. Dewatering equipment; 6. Dosing equipment; 7. Metering pump; 8. Sludge removal device; 81. Sludge suction device; 811. Sludge suction pipe; 812. Sludge suction pump; 813. Movable pipe; 8131. Sludge suction port; 814. Floating component; 82. Mud baffle; 821. Filter hole; 83. Drive component; 9. Pump body; 101. First connecting port; 102. First overflow port; 103. Second connecting port; 104. Second overflow port. Detailed Implementation

[0055] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0056] Example 1:

[0057] This application discloses an aquaculture wastewater treatment system for treating wastewater from aquaculture (such as eel) to ensure that the discharged wastewater meets standards, thereby effectively reducing the pollution of the surrounding environment caused by wastewater discharge.

[0058] Reference Figure 1 and Figure 2 The aquaculture wastewater treatment system includes an equalization tank 1, an air flotation unit 2, a biofilm tank 3, a sludge tank 4, and a dewatering unit 5. The equalization tank 1 is used to homogenize the quality and quantity of aquaculture wastewater, facilitating subsequent treatment of wastewater with concentrated pollutants. The air flotation unit 2 is used for pretreatment of aquaculture wastewater, removing most suspended solids and total phosphorus. The biofilm tank 3 uses microorganisms to treat pollutants in the wastewater, removing organic matter, ammonia nitrogen, total nitrogen, and total phosphorus. The sludge tank 4 is used to collect sludge generated during the aquaculture wastewater treatment process, such as air flotation sludge and biological sludge (i.e., biofilm), facilitating subsequent unified treatment. The dewatering unit 5 treats the sludge in the sludge tank 4, obtaining sludge cake and dewatered liquid, facilitating the off-site disposal of the sludge cake and the reuse of the dewatered liquid in the aquaculture wastewater treatment process.

[0059] A pipe is connected to the top of the equalization tank 1 to transport aquaculture wastewater into the equalization tank 1. The equalization tank 1 is connected to the flotation device 2 via a pipe that connects to the bottom of the equalization tank 1, and a pump 9 is fixedly installed on the pipe to drive the aquaculture wastewater in the equalization tank 1 into the flotation device 2. In this embodiment, since the equalization tank 1 with the above functions and the corresponding pump 9 are both existing technologies in the art, they will not be described in detail here, and the accompanying drawings only show a brief representation of them.

[0060] The flotation device 2 has two external pipes connected to the biofilm tank 3 and the sludge tank 4, respectively. These pipes are used to drive the flotation effluent and flotation sludge obtained after the wastewater pretreatment into the biofilm tank 3 and the sludge tank 4, respectively. Both the flotation effluent and the flotation sludge are transported through the pipes by gravity flow. In this embodiment, since the flotation device 2 with the above functions is prior art in this field, it will not be described in detail here, and it is only briefly shown in the accompanying drawings.

[0061] The flotation device 2 is also externally connected to a pipeline that connects to a dosing device 6 for replenishing PAC / PAM (polyaluminum chloride / polyacrylamide) into the flotation device 2. A metering pump 7 is also fixedly installed on this pipeline for replenishing PAC / PAM into the flotation device 2 at regular intervals and in measured quantities as needed. In this embodiment, since the dosing device 6 and the metering pump 7 with the above functions are both existing technologies in the art, they will not be described in detail here, and the accompanying drawings only provide a brief representation.

[0062] Reference Figure 2 and Figure 3 The biofilm tank 3 includes a primary A1 tank 31, a primary A2 tank 32, a primary O tank 33, a secondary A tank 34, and a secondary O tank 35 arranged sequentially along the flow direction of the wastewater. The effluent from the flotation equipment 2 flows into the primary A1 tank 31 through a pipe, and this pipe is connected to the space above the liquid surface in the primary A1 tank 31. In this embodiment, the arrangement direction of the primary A1 tank 31, primary A2 tank 32, primary O tank 33, secondary A tank 34, and secondary O tank 35 is not further specified. In practical applications, they are usually arranged along a straight line or a circular path.

[0063] The bottom between the primary A1 tank 31 and the primary A2 tank 32 has a first connecting port 101 for sewage flow, so that the sewage level in the primary A1 tank 31 and the primary A2 tank 32 is level; the top between the primary A2 tank and the primary O tank 33 has a first overflow port 102 for sewage flow, and the sewage level in the primary O tank 33 will be lower than the sewage level in the primary A2 tank; the bottom between the primary O tank 33 and the secondary A tank 34 has a second connecting port 103 for sewage flow, so that the sewage level in the primary O tank 33 and the secondary A tank 34 is level; the top between the secondary A tank 34 and the secondary O tank 35 has a second overflow port 104 for sewage flow, and the sewage level in the secondary O tank 35 will be lower than the sewage level in the secondary A tank 34.

[0064] During the wastewater treatment process in biofilm tank 3, nitrates in the wastewater are first removed through the denitrification capacity of primary A1 tank 31 and primary A2 tank 32. Then, a small amount of ammonia nitrogen in the wastewater is converted into nitrates in primary O tank 33. Next, a small amount of nitrates formed by nitrification in primary O tank 33 is removed in secondary A tank 34. Finally, residual organic matter in the wastewater is further removed in secondary O tank 35, and total phosphorus is adsorbed by the biofilm, thereby achieving the effects of nitrogen removal, phosphorus removal, and carbon removal.

[0065] In this embodiment, the preferred retention times for wastewater in primary A1 tank 31, primary A2 tank 32, primary O tank 33, secondary A tank 34, and secondary O tank 35 are 5h, 5h, 5h, 3h, and 4h, respectively.

[0066] Once the wastewater in the secondary A pool 34 meets the standards, it can be directly discharged through pipelines or transported back to the water-requiring links in the aquaculture system for use.

[0067] Each of the primary A1 tank 31, primary A2 tank 32, primary O tank 33, secondary A tank 34, and secondary O tank 35 is fixedly equipped with packing material 38 for microbial attachment and growth. Microorganisms form a biofilm on the packing material 38, which is mainly located in the middle area of ​​the wastewater in the tank. Specifically, the packing material 38 is positioned higher than the first connecting port 101 and the second connecting port 103 but lower than the first overflow port 102 and the second overflow port 104, ensuring that the packing material 38 remains submerged in the wastewater, facilitating contact and reaction between the wastewater and the biofilm on the packing material 38. In this embodiment, the packing material 38 is preferably a biological rope packing material 38, an elastic packing material 38, or a combination packing material 38. Since the packing material 38 with the above functions is prior art in this field, it will not be described in detail here, and only a brief representation is given in the accompanying drawings.

[0068] The primary A1 tank 31, primary A2 tank 32, and secondary A tank 34 are all externally connected to a dosing device 6 for replenishing carbon sources (such as methanol, sodium acetate, or glucose) into the tanks via pipelines. This dosing device 6 is equipped with a mechanism for replenishing carbon sources into the tanks at regular intervals and in measured quantities as needed. In this embodiment, since the dosing device 6 and the metering pump 7 with the above-mentioned functions are existing technologies in the art, they will not be described in detail here, and the accompanying drawings only provide a brief representation.

[0069] In addition, instruments capable of online measurement of ORP (oxidation-reduction potential) and pH (acidity / alkalinity) values ​​in wastewater are installed in the primary A1 tank 31, primary A2 tank 32, and secondary A tank 34, allowing staff to monitor the treatment status of wastewater in these tanks in real time. In this embodiment, it is preferable that the ORP values ​​in the primary A1 tank 31, primary A2 tank 32, and secondary A tank 34 are maintained within the range of -80 to 20 mV and the pH value within the range of 7.0 to 8.5. Since instruments with the above functions are existing technology in the field, they will not be described in detail here, and their representation is omitted in the accompanying drawings.

[0070] Both the primary O-tank 33 and the secondary O-tank 35 are equipped with aeration devices 39, which aerate the wastewater near the bottom of the tank to facilitate the reaction between microorganisms and wastewater. In this embodiment, the aeration device 39 preferably consists of a blower and a pipe for ventilation; since the aeration device 39 is prior art in the art, it will not be described in detail here, and it is only briefly shown in the accompanying drawings.

[0071] In addition, both the primary Oxygenation tank 33 and the secondary Oxygenation tank 35 are equipped with instruments capable of online measurement of dissolved oxygen levels, allowing staff to monitor the wastewater treatment status in these tanks in real time. In this embodiment, it is preferable that the dissolved oxygen levels in the primary Oxygenation tank 33 and the secondary Oxygenation tank 35 be maintained within the range of 2-4 mg / L. Since instruments with the aforementioned functions are existing technology in this field, they will not be described in detail here, and their representation is omitted from the accompanying drawings.

[0072] To promote the contact reaction between wastewater and the biofilm on the packing material 38 in the tank, it is preferable that several flow promoters 36 are installed in the primary A1 tank 31, primary A2 tank 32, and secondary A tank 34 to increase the intensity of wastewater flow within the tank. The flow promoters 36 are located near the bottom of the tank and can drive the wastewater to flow in a specified direction. The combined action of several flow promoters 36 can drive the wastewater within the tank to flow along the desired trajectory. In this embodiment, since the flow promoters 36 are prior art in the art, they will not be described in detail here, and only a brief representation is given in the accompanying drawings.

[0073] Two guide plates 37 are also fixedly installed in the primary A1 tank 31. The two guide plates 37 are vertically arranged and parallel to each other, and form three flow channels for sewage to flow through within the tank. In this embodiment, preferably, three flow promoters 36 are installed in the primary A1 tank 31, and the three flow promoters 36 are respectively located at the ends of the three flow channels, so that the sewage in the tank can circulate around the two guide plates 37, and the flow direction of the sewage between the two guide plates 37 is towards the primary A2 tank.

[0074] In this embodiment, it is preferred that two flow promoters 36 are installed in both the primary A2 tank and the secondary A tank 34, and the two flow promoters 36 are located at opposite corners in the tank, so that the sewage in the tank can circulate in a circular trajectory, and during the sewage flow, the sewage near the primary O tank 33 or near the secondary O tank 35 can overflow into the corresponding primary O tank 33 or secondary O tank 35.

[0075] During the treatment of wastewater in primary A1 tank 31, primary A2 tank 32, primary O tank 33, secondary A tank 34 and secondary O tank 35, the biofilm on the surface of the packing material 38 will detach. The detached biofilm will float on the liquid surface and affect the water quality of the wastewater flowing to the next tank. At the same time, microorganisms will multiply and continue to attach to the surface of the packing material 38 to maintain the treatment effect of the biofilm in the tank on the wastewater.

[0076] Reference Figure 2 and Figure 4 Therefore, several sludge removal devices 8 are installed in the primary A1 tank 31, primary A2 tank 32, primary O tank 33, secondary A tank 34, and secondary O tank 35 to remove the biofilm floating on the liquid surface. In this embodiment, preferably, one sludge removal device 8 is installed in each of the primary A1 tank 31, primary A2 tank 32, primary O tank 33, secondary A tank 34, and secondary O tank 35. The sludge removal device 8 is located in a corner of the tank, and the sewage can flow around the sludge removal device 8 during the flow of sewage in the tank.

[0077] Reference Figure 3 and Figure 4 The sludge removal device 8 includes a sludge suction device 81 and a baffle plate 82. The sludge suction device 81 is used to suck up the biofilm floating on the liquid surface in the pool and discharge it; the baffle plate 82 is used to intercept the biofilm floating on the liquid surface in the pool during the flow of sewage in the pool, so that the biofilm floating on the liquid surface in the pool can be concentrated around the sludge suction device 81.

[0078] Reference Figure 2 and Figure 4 The sludge suction device 81 includes a sludge suction pipe 811 and a sludge suction pump 812.

[0079] One end of the sludge suction pipe 811 is immersed in the sewage in the pool and located near the liquid surface, while the other end of the sludge suction pipe 811 is connected to the sludge pool 4. In this embodiment, preferably, the end of the sludge suction pipe 811 located in the pool has a vertically upward flared structure, and the sludge suction pipe 811 can suck up the biofilm floating on the liquid surface in the pool above it and discharge it into the sludge pool 4; and preferably, the position where the sludge suction pipe 811 sucks in the biofilm is 5-10 cm below the liquid surface.

[0080] The sludge suction pump 812 is fixedly installed on the sludge suction pipe 811, and can drive the biofilm located around the sludge suction pipe 811 in the pool to be transported into the sludge pool 4 through the sludge suction pipe 811. In this embodiment, preferably, the sludge suction pump 812 can automatically turn on for 3-10 minutes every 0.5-3 hours to remove the biofilm floating on the liquid surface in the pool, depending on the operation of the biofilm. Since the sludge suction pump 812 with the above function is the prior art in this field, it will not be described in detail here, and it is only briefly shown in the accompanying drawings.

[0081] The mudguard 82 has a rectangular plate-like structure and is fixedly installed on one side of the pool wall, located on the side of the suction pipe 811 within the pool along the direction of sewage flow. Its two ends along its length are respectively above and in the sewage. A space for biofilm accumulation is formed between the mudguard 82 and the side of the suction pipe 811 facing away from the mudguard 82 on the pool wall, and this space is constricted along the direction of sewage flow. Biofilm floating on the surface of the liquid will enter this space with the sewage flow and come into contact with the mudguard 82. The mudguard 82 can intercept the biofilm in contact with it, causing the biofilm floating on the surface to concentrate in the area near the suction pipe 811, facilitating the suction of the biofilm by the suction device 81 during operation. In this embodiment, the length of the portion of the mudguard 82 above the liquid surface is preferably 5 cm, and the length of the portion of the mudguard 82 in the sewage is preferably 10-20 cm.

[0082] Reference Figure 1 The sludge tank 4 is connected to the dewatering equipment 5 via a pipe, and a pump 9 is fixedly installed on the pipe. After the air flotation sludge produced by the air flotation equipment 2 and the biological sludge (i.e., biofilm) produced by the biofilm tank 3 are both transported to the sludge tank 4, when the sludge storage volume in the sludge tank 4 reaches a certain value, the pump 9 will drive the sludge in the sludge tank 4 to be transported into the dewatering equipment 5. In this embodiment, the dewatering equipment 5 is preferably a screw press dewatering machine; since the screw press dewatering machine is existing technology in this field, it will not be described in detail here, and it is only briefly shown in the accompanying drawings.

[0083] After the sludge is dewatered by the dewatering equipment 5, sludge cake and dewatered liquid will be obtained. The sludge cake will be transported by a special transport vehicle for further processing, and the dewatered liquid will be sent back to the equalization tank 1 through a pipeline for further processing.

[0084] The implementation principle of an aquaculture wastewater treatment system according to an embodiment of this application is as follows:

[0085] After the aquaculture wastewater is homogenized and equalized in the equalization tank 1, the wastewater with uniformly distributed pollutants is sent to the air flotation device 2 for air flotation treatment. The air flotation sludge obtained after air flotation treatment is sent to the sludge tank 4, and the air flotation effluent is sent to the biofilm tank 3 to remove pollutants such as organic matter, nitrogen, and phosphorus from the wastewater. After the wastewater in the biofilm tank 3 is treated to meet the standards, it is discharged. The sludge removal device 8 sucks in the aged biofilm that has detached from the packing material 38 during the operation of the biofilm tank 3 and discharges it to the sludge tank 4. When the sludge in the sludge tank 4 reaches a certain amount, the sludge in the sludge tank 4 is sent to the dewatering device 5 for dewatering. The sludge cake obtained after dewatering is transported out for further processing, and the dewatered clear liquid is sent back to the equalization tank 1 to continue to participate in the treatment of aquaculture wastewater.

[0086] Example 2:

[0087] Reference Figure 4 and Figure 5 The difference between this embodiment and Embodiment 1 is the mud removal device 8.

[0088] Reference Figure 5 and Figure 6 To facilitate the suction of biofilm floating on the surface of the tank by the sludge suction device 81, reduce the probability of sewage being discharged through the suction pipe 811 along with the biofilm, and improve the removal effect of the sludge removal device 8 on the biofilm, the sludge suction device 81 preferably also includes a movable pipe 813 and a floating component 814, and preferably the end of the suction pipe 811 located in the tank is a circular pipe structure.

[0089] One end of the movable tube 813 is fitted with the end of the sludge suction tube 811 located in the pool and is movably connected to the sludge suction tube 811. The movable tube 813 moves vertically and remains fitted with the sludge suction tube 811 during its movement.

[0090] The top of the active tube 813 has an upwardly flared structure, forming a sludge suction port 8131 for the biofilm floating on the liquid surface in the pool to enter the active tube 813. After entering the active tube 813 through the sludge suction port 8131, the biofilm can enter the sludge suction pipe 811 along the active tube 813.

[0091] The floating element 814 has the effect of floating on the liquid surface, meaning that the density of the floating element 814 is less than the density of the sewage. The floating element 814 is fixedly installed at the top of the movable pipe 813 and located at the suction port 8131, ensuring that the suction port 8131 remains at a height no higher than the liquid surface in the sewage. Simultaneously, the floating element 814 reduces the area where the biofilm enters the movable pipe 813 through the suction port 8131, increasing the suction force of the sludge suction device 81 on the biofilm and improving the biofilm suction effect. In this embodiment, preferably, the suction port 8131, under the floating action of the floating element 814, will remain 1-3 cm below the liquid surface.

[0092] Reference Figure 5 and Figure 7 To improve the interception effect of the mudguard 82 on the biofilm floating on the liquid surface in the pool, it is preferable that the mudguard 82 has an arc-shaped plate structure, the axis of the arc trajectory of the mudguard 82 is vertical, and the arc opening of the mudguard 82 faces the mud suction port 8131.

[0093] When the biofilm floating on the surface of the liquid in the pool comes into contact with the baffle plate 82 as the sewage flows in the pool, the biofilm will come into contact with the arc-shaped concave surface of the baffle plate 82. The arc-shaped concave surface structure of the baffle plate 82 gives it a larger space for the biofilm to stay, thereby enabling more biofilm to concentrate in the area near the suction port 8131.

[0094] Furthermore, in order to take into account the interception effect of the mudguard 82 on the biofilm floating on the liquid surface in the pool, and at the same time reduce the impact of the mudguard 82 on the flow of sewage in the pool, it is preferable that the mudguard 82 has multiple filter holes 821 for filtering the biofilm, and the multiple filter holes 821 are evenly distributed on the mudguard 82.

[0095] When the biofilm floating on the surface of the pool comes into contact with the baffle plate 82 as the sewage flows through the pool, the baffle plate 82 can intercept the biofilm, while the sewage can pass through the baffle plate 82 through multiple filter holes 821.

[0096] Reference Figure 5 and Figure 8 Furthermore, in order to further improve the suction effect and efficiency of the sludge suction device 81 on the biofilm floating on the liquid surface in the pool during operation, it is preferable that the baffle plate 82 is rotatably connected to the pool body, and it is preferable that the sludge removal device 8 also includes a driving component 83 for driving the baffle plate 82 to rotate.

[0097] One end of the arc-shaped trajectory of the mudguard 82 is rotatably connected to the pool body, and the rotation axis of the mudguard 82 is vertical; the driving component 83 is fixedly installed on the pool body and can drive the mudguard 82 to rotate relative to the pool body. In this embodiment, the driving component 83 is preferably a servo motor; since servo motors are common existing technology, they will not be described in detail here, and are only briefly shown in the accompanying drawings.

[0098] The drive component 83 has limitations in the process of driving the mudguard 82 to rotate.

[0099] Reference Figure 7 and Figure 8 When the baffle plate 82 rotates to its limit position away from the suction port 8131, the space formed between the baffle plate 82 and the pool wall on the side away from the baffle plate 82 and the suction pipe 811 on the pool body is narrowed along the flow direction of the sewage in the pool, which makes it easier for the biofilm intercepted by the baffle plate 82 to stay in the area near the suction port 8131.

[0100] Subsequently, when the baffle plate 82 rotates to its limit position towards the suction port 8131, the space formed between the baffle plate and the pool wall on the side of the suction pipe 811 away from the baffle plate 82 expands along the flow direction of the sewage in the pool. This can gather the biofilm that previously stayed in the area near the suction port 8131, making the biofilm closer to the suction port 8131. At the same time, it can reduce the impact of sewage flow on the movement of biofilm near the suction port 8131. Furthermore, during the operation of the suction device 81, it has a suction effect on the sewage around the suction port 8131. The sewage that moves under its influence can pass through the filter hole 821 in the opposite direction, which has a clearing effect on the filter hole 821 (the blockage is biofilm). At the same time, it can accelerate the entry of the biofilm gathered by the baffle plate 82 into the suction port 8131.

[0101] Furthermore, to further improve the cleaning effect of sewage flow on the filter holes 821 on the mudguard 82, it is preferable that the filter holes 821 are narrowed in the direction close to the arc trajectory axis of the mudguard 82, so that sewage can pass through the filter holes 821 and pass through the mudguard 82 in the reverse direction.

[0102] The implementation principle of an aquaculture wastewater treatment system according to an embodiment of this application is as follows:

[0103] During the treatment of wastewater in the biofilm tank 3, when the sludge removal device 8 is running, the movable pipe 813 can move relative to the sludge suction pipe 811 according to the height of the liquid level in the tank, so that the biofilm floating on the liquid surface in the tank can smoothly and quickly enter the sludge suction pipe 811 through the sludge suction port 8131 and be discharged.

[0104] Meanwhile, under the control of the drive component 83, the baffle plate 82 can rotate to its limit position and remain in the direction away from the suction port 8131 during the standby process of the sludge removal device 8, so that more biofilm floating on the liquid surface in the pool can stay in the area near the suction port 8131; and before the sludge removal device 8 is running, the baffle plate 82 can rotate in the direction closer to the suction port 8131, so that the biofilm staying in the area near the suction port 8131 can gather in the direction closer to the suction port 8131, which is convenient for the subsequent suction and discharge of biofilm; during the operation of the sludge removal device 8, the sewage flowing towards the suction port 8131 due to the influence of the sludge removal device 8 can pass through the filter hole 821, which can clear the filter hole 821 and accelerate the entry of biofilm around the suction port 8131 into the suction port 8131.

[0105] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An aquaculture wastewater treatment system, characterized in that, It includes an equalization tank (1), an air flotation device (2), a biofilm tank (3), a sludge tank (4), and a dewatering device (5); The regulating tank (1) is used for equalizing the quality and quantity of aquaculture wastewater, and the bottom of the regulating tank (1) is connected to the air flotation device (2) through a pipe. The air flotation device (2) is connected to the biofilm tank (3) by a pipeline for conveying the aquaculture tailwater after air flotation, and the air flotation device (2) is connected to the sludge tank (4) by a pipeline for conveying the air flotation sludge. A pipe for transporting aged biofilm is connected between the biofilm tank (3) and the sludge tank (4); a pipe for transporting sludge is connected between the sludge tank (4) and the dewatering equipment (5), and the dewatered liquid obtained by the dewatering equipment (5) can be sent back to the equalization tank (1). The biofilm tank (3) includes a primary A1 tank (31), a primary A2 tank (32), a primary O tank (33), a secondary A tank (34), and a secondary O tank (35) distributed sequentially along the sewage flow direction, and each tank is equipped with packing material (38) for microorganisms to attach and grow. The bottom of the primary A1 pool (31) and the primary A2 pool (32) has a first connecting port (101), the top of the primary A2 pool (32) and the primary O pool (33) has a first overflow port (102), the bottom of the primary O pool (33) and the secondary A pool (34) has a second connecting port (103), and the top of the secondary A pool (34) and the secondary O pool (35) has a second overflow port (104). Both the primary O tank (33) and the secondary O tank (35) are equipped with aeration devices (39). Each of the primary A1 tank (31), the primary A2 tank (32), the primary O tank (33), the secondary A tank (34), and the secondary O tank (35) is equipped with a sludge removal device (8); The sludge removal device (8) includes a sludge suction device (81) and a baffle plate (82); the sludge suction device (81) includes a sludge suction pipe (811) and a sludge suction pump (812); one end of the sludge suction pipe (811) is connected to the sludge tank (4) and is located in a corner of the tank, while the other end is immersed in the liquid and close to the liquid surface; the sludge suction pump (812) is installed on the sludge suction pipe (811) and can drive the biofilm located on the liquid surface in the tank to be sent into the sludge tank (4) through the sludge suction pipe (811). The mudguard (82) is installed in the pool, with part of the mudguard (82) above the liquid surface and part of it immersed in the liquid, and located on one side of the end of the suction pipe (811) along the direction of sewage flow in the pool; The mudguard (82) has multiple filter holes (821) for filtering biofilm. The mudguard (82) has an arc-shaped plate structure, and the axis of the arc trajectory of the mudguard (82) is vertical; The sludge removal device (8) also includes a drive unit (83); One end of the arc-shaped trajectory of the mudguard (82) is rotatably connected to the pool body, and the rotation axis of the mudguard (82) is vertical; the driving component (83) is provided on the pool body and can drive the mudguard (82) to rotate; When the mudguard (82) rotates to its limit position away from the suction pipe (811), the pool wall on the side of the mudguard (82) away from the mudguard (82) and the suction pipe (811) flares out along the direction of sewage flow in the pool. When the mudguard (82) rotates to its limit position in the direction close to the suction pipe (811), the pool wall on the side of the mudguard (82) away from the mudguard (82) and the suction pipe (811) is constricted along the direction of sewage flow in the pool.

2. The aquaculture wastewater treatment system according to claim 1, characterized in that, The sludge suction device (81) also includes a movable tube (813) and a floating component (814). The movable tube (813) is movably connected to the end of the sludge suction tube (811) in the pool. The movable tube (813) moves vertically and remains in communication with the sludge suction tube (811) during its movement. The top of the active tube (813) has a sludge suction port (8131), and the floating member (814) is disposed on the top of the active tube (813); the floating member (814) floats on the liquid surface, so that the position of the sludge suction port (8131) is kept no higher than the liquid surface, and the biofilm floating on the liquid surface can enter the sludge suction port (8131).

3. The aquaculture wastewater treatment system according to claim 1, characterized in that, The filter hole (821) is constricted in the direction of the suction pipe (811).

4. The aquaculture wastewater treatment system according to claim 1, characterized in that, Each of the first-stage A1 pool (31), the first-stage A2 pool (32), and the second-stage A pool (34) is equipped with a number of flow promoters (36). The flow promoter (36) is located near the bottom of the pool, and several of the flow promoters (36) are capable of driving the sewage to flow in the pool along a circular trajectory.

5. The aquaculture wastewater treatment system according to claim 4, characterized in that, The primary A1 pool (31) is also provided with several guide plates (37), and the several guide plates (37) are separated in the pool to form several flow channels.

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