Biological purification device for breeding circulating water

Abstract

According to the biological purification device, a generator is connected with a storage battery, and the storage battery is connected with a driving circuit; one end of the drainage pipe is connected with the water pump, the other end of the drainage pipe is arranged above the water tank, the water tank is arranged on the upper right portion of the shell, a drainage plate of the drainage pipe faces the inclined filter screen, the right end of the inclined filter screen is hinged to the right side of the culture pond, the left side of the inclined filter screen is arranged at the upper end of a middle inclined step, and the left end of the inclined filter screen is arranged on the upper right portion of the decomposition pond; the filter plate is arranged in a middle hole of a middle inclined step for separating the shell into the decomposition tank and the culture tank and is communicated with the decomposition tank and the culture tank; the gas-lift filter is arranged at the bottom of the culture pond and connected with the reversing valve through a left gas pipe, a right gas pipe and a middle gas pipe, and the reversing valve is connected with the gas pump through a gas supply pipe. The power generator is uniform in output electric quantity, the gas lift filter can accurately adjust the PH value of a water body, and secondary pollution is avoided; the organic solid waste treatment speed of loaches and scavengers in the decomposition tank is far higher than that of plants, microorganisms, reeds and water hyacinth, inorganic salt is filtered in a three-dimensional mode, and the space utilization rate is high.

Description

Technical Field

[0001] This utility model relates to the field of aquaculture, and in particular to a biological purification system for recirculating aquatic water used in aquaculture driven by photovoltaic power generation. Background Technology

[0002] With increasingly stringent environmental impact assessment standards, the government is also strengthening its control over aquaculture wastewater. Compared with traditional water exchange methods, aquaculture recirculating aquaculture biological purification devices can utilize water resources more effectively, reduce aquaculture wastewater discharge, and are more in line with the green development trend of the aquaculture industry.

[0003] Impurities filtered out by the circulating water system are usually decomposed by organisms and then pumped back into the aquaculture pond to form circulating water. Existing biological circulating water systems typically use microorganisms to nitrify organic waste and then use floating hulls to grow plants to absorb the nitrified inorganic matter. The decomposition rate is limited by the metabolism of microorganisms and plants. The nitrification and denitrification processes also heavily rely on air pumps for oxygenation. The system is complex and consumes a lot of oxygen, so it can be said to save water but not electricity.

[0004] While photovoltaic power generation and energy storage equipment can provide power supplements to circulating water devices, the flat photovoltaic panels used are greatly affected by the angle of direct sunlight, resulting in uneven power output. They require an automatic steering mechanism to track the angle of direct sunlight, making the structure complex and increasing manufacturing and maintenance costs. Curved photovoltaic panels, on the other hand, have a larger light absorption area for the same size and greater angle compatibility, with lower requirements for the angle of direct sunlight, thus improving power generation efficiency and making the power output more uniform. However, curved photovoltaic panels are also significantly affected by the different angles of direct sunlight in different seasons.

[0005] Inclined screen solid waste separators are commonly used solid waste separation devices in aquaculture recirculating aquaculture systems. When water flows through an inclined screen, most of the water seeps out through the screen's pores under gravity, while the remaining water is diverted by the screen to flush away the solid waste residue filtered out. This type of separator has issues with water consumption and filtration efficiency. For example, a small inclination of the screen results in good permeability and low water consumption, but also a small water separation volume, poor rinsing effect, and easy sedimentation, leading to screen blockage. Increasing the inclination increases the screen's drainage effect and water separation volume, improving rinsing efficiency, but reduces permeability and increases water consumption. Furthermore, the screen's filtration precision is relatively low, typically used for coarse filtration.

[0006] Airlift filters utilize the lifting effect generated by the rising of air bubbles in the water. Driven by an air pump, the water flow is controlled by the airflow, which is small and slow. The filter screen can better adsorb fine particles, and the neutralizing filter media can also fully neutralize the pH value of the water, making it suitable for fine filtration after coarse filtration. However, existing airlift filters all adopt a single-chamber structure, making it difficult to accurately adjust the pH value of the water according to the needs of aquaculture. Utility Model Content

[0007] The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a biological purification device for aquaculture recirculating water that is biologically cyclical, environmentally friendly and energy-saving, can regulate the pH value of water, consumes little water, and has no secondary pollution.

[0008] This utility model specifically describes a biological purification device for aquaculture recirculating aquaculture systems, comprising: a generator, a battery, a water pump, a water tank, a housing, an inclined filter, a decomposition tank, a filter plate, a middle inclined step, an aquaculture pond, an air-lift filter, a reversing valve, an air pump, a drive circuit, and related connecting pipes: a drain pipe, a water inlet pipe, an air supply pipe, a left air pipe, a right air pipe, and a middle air pipe; the generator is connected to the battery via wires, and the battery is connected to the drive circuit via wires; the water pump is located outside the housing, the inlet of the water inlet pipe is connected to the bottom of the aquaculture pond, and the outlet is connected to the water pump inlet; the inlet of the drain pipe is connected to the water pump. The water outlet and drain pipe outlet are located above the water tank, which is located on the upper right side of the shell. Its guide plate faces the inclined filter screen. The upper right end of the inclined filter screen is hinged to the upper right side of the aquaculture tank. The left side is located at the upper end of the middle inclined step, and the left end is located on the upper right side of the decomposition tank. The middle inclined step separates the inner cavity of the shell into the decomposition tank on the left and the aquaculture tank on the right. The decomposition tank and the aquaculture tank are connected through the middle hole. The filter plate is placed in the middle hole of the middle inclined step. The air lift filter is located at the bottom of the aquaculture tank. It is connected to the air outlet of the reversing valve through the left air pipe, the right air pipe, and the middle air pipe. The air inlet of the reversing valve is connected to the air outlet of the air supply pipe, and the air inlet of the air supply pipe is connected to the air pump.

[0009] The generator includes: an arc-shaped photovoltaic panel, a support column, a support base, a threaded telescopic rod, and a base. The upper end of the support column is fixedly connected to the center of the back surface of the arc-shaped photovoltaic panel, the lower end of the support column is movably hinged to the upper end of the support base, the lower end of the support base is centered and fixedly connected to the base, the upper end of the threaded telescopic rod is movably hinged to the edge of the arc-shaped photovoltaic panel, and the lower end is movably hinged to the base. The six components are evenly distributed in a ring.

[0010] The drive circuit includes: a time switch, a changeover switch, a water pump motor, and an air pump motor. The time switch is connected in series with the changeover switch, and the changeover switch is connected in parallel with the water pump motor and the air pump motor.

[0011] The water tank includes: a water collection tank and a diversion plate; the water collection tank is located on the upper right side of the aquaculture pond, with the right side higher than the left side; the right end of the diversion plate is fixedly connected to the left side of the water collection tank, and the left end faces the inclined filter screen.

[0012] The inclined filter screen is an upwardly convex arc-shaped screen, with the right side higher than the left.

[0013] The decomposition tank contains nitrified water, with reeds planted at the bottom and water hyacinths raised on the surface, and loach and scavengers are also introduced.

[0014] The airlift filter includes: a cylinder, a partition, a duckbill rubber valve, a steam pipe, an upper grid plate, biochemical cotton, packing material, a bottom plate, a lower grid plate, and a middle grid plate. The partition plate divides the cylinder into a left chamber, a middle chamber, and a right chamber. The bottom of the cylinder is fixedly connected to the bottom plate. The lower end of the bottom plate is flat and flush with the bottom of the shell. The upper edge of the bottom plate has a sloping step to position and support the lower grid plate. The gap between the lower grid plate and the bottom plate forms a return water chamber. The middle grid plate is above the lower grid plate. The middle grid plate is filled with filler, and the upper grid plate is above the middle grid plate. Biochemical cotton is sandwiched between the upper and middle grid plates. The lower end of the water vapor pipe is fixedly connected to the middle hole of the lower grid plate, connecting to the return water chamber. The middle section of the water vapor pipe is sleeved in the middle hole of the upper and middle grid plates, and the upper end of the water vapor pipe is sleeved with a duckbill rubber valve. The left air pipe, right air pipe, and middle air pipe are located above the upper grid plate and connected to the water vapor pipe. The exhaust ports of the left air pipe, right air pipe, and middle air pipe are below the duckbill rubber valve.

[0015] The fillers include: carbonized straw, green pumice, and aquatic plant mud. The filler in the left chamber of the air-lift filter is green pumice, the filler in the middle chamber is carbonized straw, and the filler in the right chamber is aquatic plant mud.

[0016] The reversing valve is a three-position four-way rotary valve. The air inlet is connected to the air supply pipe, the left air outlet is connected to the left air pipe, the middle air outlet is connected to the middle air pipe, and the right air outlet is connected to the right air pipe. The left-hand air supply pipe is connected to the left air pipe, the middle air supply pipe is connected to the middle air pipe, and the right-hand air supply pipe is connected to the right air pipe.

[0017] The working principle of this utility model power device is as follows: the lower end of the generator's support column is connected to the upper end of the support by a movable hinge. By adjusting the threaded telescopic rod, the angle of the arc-shaped photovoltaic panel can be adjusted so that it can be directly exposed to the midday sun for different solar terms, thereby obtaining more electricity. The arc-shaped photovoltaic panel has high angle compatibility, low requirements for the angle of direct sunlight, requires fewer adjustments, and can provide more uniform power supply to the battery.

[0018] The battery acts as a constant voltage source for the drive circuit, ensuring the stable operation of the water pump motor and air pump motor. Based on the impact of day and night length on power generation in winter and summer, and the different requirements of water temperature on nitrification water filtration and aeration in winter and summer, a time switch is set to precisely control the working time in different seasons according to the power generation in different seasons, so as to meet the working needs of different seasons. During coarse filtration, the selector switch connects to the water pump motor, and during fine filtration, the selector switch switches to the air pump motor.

[0019] The working principle of the water circulation of this utility model is as follows: During coarse filtration, the selector switch turns on the water pump motor, and the water pump draws water from the bottom of the breeding pond through the inlet pipe and supplies water to the water tank through the drain pipe. The water accumulated in the water tank flows to the inclined screen through the diversion plate. Due to the inclination angle of the inclined screen, the separated solid waste will be flushed into the decomposition tank by the diversion water, and the separated water falls back into the breeding pond through the mesh.

[0020] The inclined screen is an upward-convex arc-shaped screen, arranged with the right side higher than the left, so that the inclination angle on the left side is greater than that on the right side. The right side of the inclined screen is located below the water tank's diversion plate, and the water flow from the diversion plate directly impacts the right side of the inclined screen, resulting in a large water flow and good rinsing effect. The inclination angle on the right side of the inclined screen is smaller than that on the left side, resulting in good water permeability. After the separated water falls back into the aquaculture pond through the mesh, the water flow on the left side of the inclined screen gradually decreases, but the inclination angle on the left side is greater than that on the right side, so the diverted water volume gradually increases, resulting in a good rinsing effect. The upward-convex arc-shaped screen structure effectively balances water consumption and rinsing effect, and can effectively reduce water diversion and water consumption while ensuring rinsing effect.

[0021] In the decomposition tank, loaches and plecos consume the separated solid waste impurities. Plecos have a large appetite and are highly efficient at removing solid waste impurities, while loaches are adept at squeezing into crevices, which helps clean nooks and crannies. The excrement digested by loaches and plecos undergoes a significantly faster nitrification process. Animals have a much higher metabolic rate than plants and microorganisms, and their processing speed for organic solid waste is also higher than that of plants and microorganisms. Loaches and plecos can breathe air directly, thus reducing their oxygen consumption. The reeds planted at the bottom of the decomposition tank and the water hyacinths raised on the surface are arranged in a staggered pattern, making full use of the limited space in the decomposition tank for three-dimensional filtration, absorbing the inorganic salts produced after nitrification.

[0022] Water hyacinth can be processed into green fodder for aquaculture; reeds can be processed into carbonized straw, which can be used as packing material for airlift filters; thus forming a virtuous cycle.

[0023] During coarse filtration, the diverted water flows into the decomposition tank along with the solid waste. The water level in the aquaculture tank drops, while the water level in the decomposition tank rises. The water in the decomposition tank is filtered through the filter plate at the central hole of the inclined step and then seeps into the aquaculture tank, completing the coarse filtration cycle.

[0024] After coarse filtration, the switch is turned on to activate the air pump motor, the reversing valve is set to center, and the air-lift filter is started to finely filter the water in the aquaculture pond. The air pump is connected to the middle air pipe through the air supply pipe, which supplies air to the water-air pipe in the middle cavity to increase pressure and form bubbles. When the bubbles are discharged through the duckbill rubber valve, they will carry out some water from the water-air pipe. The water-air pipe draws water from the return water chamber through the lower end orifice, generating negative pressure. Under the action of water pressure, the water in the aquaculture pond enters the middle cavity of the air-lift filter from the upper grid plate, and after fine filtration through biochemical cotton and carbonized straw, it enters the return water chamber and then enters the water-air pipe to complete the fine filtration cycle. Aeration and fine filtration are completed in one step.

[0025] When the water in the aquaculture pond is acidic, the reversing valve turns counterclockwise, connecting the air supply pipe to the left air pipe. This pressurizes the water vapor pipe in the left chamber, forming bubbles. When the bubbles are discharged through the duckbill rubber valve, they carry some water out of the water vapor pipe. The water vapor pipe draws water from the return water chamber through the lower orifice, creating negative pressure. Under this water pressure, the water in the aquaculture pond enters the left chamber of the air-lift filter from the upper grid plate. After being filtered by biochemical cotton and neutralized by green pumice, the water enters the return water chamber and then the water vapor pipe, completing the circulation. When the water in the aquaculture pond is alkaline, the reversing valve turns clockwise, connecting the air supply pipe to the right air pipe. This pressurizes the water vapor pipe in the right chamber, forming bubbles. When the bubbles are discharged through the duckbill rubber valve, they carry some water out of the water vapor pipe. The water vapor pipe draws water from the return water chamber through the lower orifice, creating negative pressure. Under this pressure, the water in the aquaculture pond enters the right chamber of the air-lift filter from the upper grid plate. After being filtered by biochemical cotton and neutralized by aquatic plant mud, the water enters the return water chamber and then the water vapor pipe, completing the circulation.

[0026] Compared with the existing technology, the present invention has the following advantages:

[0027] The generator of this invention has a compact structure, low manufacturing and maintenance costs, and more uniform power output. The threaded telescopic rod of the generator can adjust the angle of the arc-shaped photovoltaic panel, so that it can be directly exposed to the midday sun for different seasons to obtain more power. The arc-shaped photovoltaic panel has high angle compatibility, low requirements for the angle of direct sunlight, requires fewer adjustments, does not require an automatic steering mechanism, and can provide more uniform power supply to the battery.

[0028] This utility model's time switch can precisely control the working time of different seasons according to the power generation in different seasons, meeting the working needs of different seasons. In summer, the water temperature is high, nitrifying bacteria multiply rapidly, aquatic metabolism is fast, oxygen consumption is high, and water quality changes rapidly. However, in summer, the days are long and the nights are short, so the generator can deliver more power to the battery. Both the coarse filtration cycle and the fine filtration cycle can extend their working time to maintain water quality stability. In winter, the water temperature is low, nitrifying bacteria multiply slowly, aquatic metabolism is slow, oxygen consumption is low, and water quality changes are slow. However, in winter, the days are short and the nights are long, so the generator delivers less power to the battery. Both the coarse filtration cycle and the fine filtration cycle can be appropriately shortened according to the battery power to maintain water quality stability.

[0029] The inclined screen of this utility model is an upwardly convex arc-shaped screen, arranged with the right side higher than the left side, and the inclination angle of the left side is greater than that of the right side. According to the water flow rate, the water distribution can be controlled, which can effectively reduce the water distribution and reduce water consumption while ensuring the rinsing effect.

[0030] The airlift filter of this invention can use three different packing materials to neutralize the water quality according to the acidity or alkalinity of the aquaculture pond water, and precisely adjust the pH value to the pH value required by aquaculture.

[0031] The duckbill rubber valve of this utility model air-lift filter is sleeved at the upper end of the water-air pipe and acts as a check valve to prevent water from flowing back into the air-lift filter through the water-air pipe when the air-lift filter is not working, thus avoiding unnecessary acidification or alkalization reactions.

[0032] This invention does not produce secondary pollution. The filler material of the air-lift filter is carbonized straw, green pumice, and aquatic plant mud. All three can be used as soil fillers. The filler material after the air-lift filter is used can be directly used for fertilization of cultivated land. The sediment in the decomposition tank can also be used for fertilization of cultivated land or processed into nutrient soil.

[0033] The water hyacinth in the decomposition tank of this invention can be processed into green fodder for aquaculture; the reeds can be processed into carbonized straw to serve as packing material for airlift filters, thus forming a virtuous cycle.

[0034] The loach and scavenger of this invention can breathe air directly with low oxygen consumption; the excrement after digestion by the loach and scavenger undergoes significantly faster nitrification and decomposition, and the animal's metabolic rate is much higher than that of plants and microorganisms, so the processing speed of organic solid waste is also higher than that of plants and microorganisms; the scavenger has a large appetite and is highly efficient at removing solid waste impurities, and the loach is good at squeezing into crevices, which is conducive to cleaning nooks and crannies.

[0035] This invention combines reeds and water hyacinths at different heights to make full use of the limited space in the decomposition tank, achieving three-dimensional filtration with high filtration efficiency and high space utilization. Attached Figure Description

[0036] Figure 1 A schematic diagram of the structure of this utility model;

[0037] Figure 2 A schematic diagram of the generator structure of this utility model;

[0038] Figure 3 The circuit diagram of the driving circuit of this utility model;

[0039] Figure 4 A schematic diagram of the water tank structure of this utility model;

[0040] Figure 5 A schematic diagram of the structure of the air-lift filter of this utility model;

[0041] Figure 6 Top view of the airlift filter of this utility model. Detailed Implementation

[0042] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6As shown, this utility model is a biological purification device for aquaculture recirculating water, including: a generator 1, a battery 2, a water pump 3, a water tank 4, a shell 5, an inclined filter 6, a decomposition tank 7, a filter plate 8, a middle inclined step T, an aquaculture tank 9, an air-lift filter 10, a reversing valve 11, an air pump 12, a drive circuit 13, and related connecting pipes: a drain pipe Q1, a water inlet pipe Q2, an air supply pipe P1, a left air pipe P2, a right air pipe P3, and a middle air pipe P4; the generator 1 is connected to the battery 2 via wires, and the battery 2 is connected to the drive circuit 13 via wires; the water pump 3 is located outside the shell 5, the inlet of the water inlet pipe Q2 is connected to the bottom of the aquaculture tank 9, and the outlet is connected to the inlet of the water pump 3; the inlet of the drain pipe Q1 is connected to the outlet of the water pump 3. The outlet of drain pipe Q1 is above water tank 4, which is located on the upper right side of shell 5. Its guide plate 4-2 faces the inclined filter screen 6. The upper right end of the inclined filter screen 6 is hinged to the upper right side of the breeding tank 9. The left side is located at the upper end of the middle inclined step T, and the left end is located on the upper right side of the decomposition tank 7. The middle inclined step T isolates the inner cavity of shell 5 into the decomposition tank 7 on the left and the breeding tank 9 on the right. The decomposition tank 7 and the breeding tank 9 are connected through the middle hole Q3. The filter plate 8 is placed in the middle hole Q3 of the middle inclined step T. The air lift filter 10 is at the bottom of the breeding tank 9. It is connected to the outlet of the reversing valve 11 through the left air pipe P2, the right air pipe P3, and the middle air pipe P4. The inlet of the reversing valve 11 is connected to the outlet of the air supply pipe P1. The inlet of the air supply pipe P1 is connected to the air pump 12.

[0043] The generator 1 includes: an arc-shaped photovoltaic panel 1-1, a support column 1-2, a support 1-3, a threaded telescopic rod 1-4, and a base 1-5. The upper end of the support column 1-2 is fixedly connected to the center of the backlight surface of the arc-shaped photovoltaic panel 1-1, and the lower end of the support column 1-2 is movably hinged to the upper end of the support 1-3. The lower end of the support 1-3 is centered and fixedly connected to the base 1-5. The upper end of the threaded telescopic rod 1-4 is movably hinged to the edge of the arc-shaped photovoltaic panel 1-1, and the lower end is movably hinged to the base 1-5. The six components are evenly distributed in a ring.

[0044] The drive circuit 13 includes: a time switch 13-1, a changeover switch 13-2, a water pump motor 13-3, and an air pump motor 13-4. The time switch 13-1 is connected in series with the changeover switch 13-2, and the changeover switch 13-2 is connected in parallel with the water pump motor 13-3 and the air pump motor 13-4.

[0045] The water tank 4 includes: a water collection tank 4-1 and a diversion plate 4-2; the water collection tank 4-1 is located above the right side of the breeding pond 9, with its right side higher than its left side; the right end of the diversion plate 4-2 is fixedly connected to the left side of the water collection tank 4-1, and its left end faces the inclined filter screen 6.

[0046] The inclined filter screen 6 is an upwardly convex arc-shaped screen, with the right side higher than the left.

[0047] The decomposition tank 7 contains nitrified water, with reeds planted at the bottom and water hyacinths raised on the surface, and loach and scavengers are introduced.

[0048] The airlift filter 10 includes: a cylinder 10-1, a partition 10-2, a duckbill rubber valve 10-3, a water vapor pipe 10-4, an upper grid plate 10-5, biochemical cotton 10-6, packing material 10-7, a bottom plate 10-8, a lower grid plate 10-9, and a middle grid plate 10-10. The partition 10-2 divides the cylinder 10-1 into a left chamber, a middle chamber, and a right chamber. The bottom of the cylinder 10-1 is fixedly connected to the bottom plate 10-8. The lower end of the bottom plate 10-8 is flat and flush with the bottom of the shell 5. The upper edge of the bottom plate 10-8 has a stepped slope to position and support the lower grid plate 10-9. The gap between the lower grid plate 10-9 and the bottom plate 10-8 forms a return water chamber. The middle grid plate 10-10 is above the lower grid plate 10-9. 0-9, the middle grid plate 10-10 is filled with filler 10-7, the upper grid plate 10-5 is above the middle grid plate 10-10, and the upper grid plate 10-5 and the middle grid plate 10-10 are sandwiched with biochemical cotton 10-6; the lower end of the water vapor pipe 10-4 is fixedly connected to the middle hole of the lower grid plate 10-9, and connects to the return water chamber. The middle section of the water vapor pipe 10-4 is sleeved in the middle hole of the upper grid plate 10-5 and the middle grid plate 10-10. The upper end of the water vapor pipe 10-4 is sleeved with the duckbill rubber valve 10-3; the left air pipe P2, the right air pipe P3, and the middle air pipe P4 are located above the upper grid plate 10-5 and are connected to the water vapor pipe 10-4. The exhaust ports of the left air pipe P2, the right air pipe P3, and the middle air pipe P4 are sleeved inside the duckbill rubber valve 10-3.

[0049] The fillers 10-7 include: carbonized straw, green pumice, and aquatic plant mud. The filler in the left cavity of the airlift filter 10 is green pumice, the filler in the middle cavity is carbonized straw, and the filler in the right cavity is aquatic plant mud.

[0050] The reversing valve 11 is a three-position four-way rotary valve. The air inlet is connected to the air supply pipe P1, the left air outlet is connected to the left air pipe P2, the middle air outlet is connected to the middle air pipe P4, and the right air outlet is connected to the right air pipe P3. When the reversing valve 11 rotates to the left, the air supply pipe P1 is connected to the left air pipe P2; when the air supply pipe P1 is rotated to the middle, it is connected to the middle air pipe P4; and when the air supply pipe P1 rotates to the right, it is connected to the right air pipe P3.

Claims

1. A biological purification device for aquaculture recirculating aquaculture systems, comprising: The system includes a generator, battery, water pump, water tank, housing, inclined filter, decomposition tank, filter plate, intermediate inclined step, aquaculture tank, air-lift filter, reversing valve, air pump, drive circuit, and related connecting pipes: drain pipe, inlet pipe, air supply pipe, left air pipe, right air pipe, and middle air pipe; the generator connects to the battery, and the battery connects to the drive circuit; the water pump is located on the outside of the housing, one end of the inlet pipe connects to the bottom of the aquaculture tank, and the other end connects to the water pump; one end of the drain pipe connects to the water pump, and the other end is above the water tank, which is located on the upper right side of the housing, with its drainage plate... The filter is oriented towards an inclined screen, with its upper right end hinged to the upper right side of the aquaculture tank. The left side is located at the upper end of the central inclined step, and the left end is located above the right side of the decomposition tank. The central inclined step separates the inner cavity of the shell into a decomposition tank on the left and an aquaculture tank on the right, connected by a central hole. The filter plate is placed in the central hole of the central inclined step. An air-lift filter is located at the bottom of the aquaculture tank. The air-lift filter is characterized by being connected to the outlet of a reversing valve via a left air pipe, a right air pipe, and a central air pipe. The inlet of the reversing valve is connected to the outlet of an air supply pipe, and the inlet of the air supply pipe is connected to an air pump.

2. The biological purification device for aquaculture recirculating water according to claim 1, characterized in that: The generator includes: an arc-shaped photovoltaic panel, a support column, a support base, a threaded telescopic rod, and a base. The upper end of the support column is fixedly connected to the center of the back surface of the arc-shaped photovoltaic panel, the lower end of the support column is movably hinged to the upper end of the support base, the lower end of the support base is centered and fixedly connected to the base, the upper end of the threaded telescopic rod is movably hinged to the edge of the arc-shaped photovoltaic panel, and the lower end is movably hinged to the base. The six components are evenly distributed in a ring.

3. A biological purification device for aquaculture recirculating water according to claim 1 or 2, characterized in that: The inclined filter screen is an upwardly convex arc-shaped screen, with the right side higher than the left.

4. The biological purification device for aquaculture recirculating water according to claim 3, characterized in that: The baffle of the air-lift filter divides the cylinder into a left chamber, a middle chamber, and a right chamber, and the exhaust port of the water vapor pipe is fitted with a duckbill rubber valve.

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