A device and method for deeply removing suspended solids in circulating aquaculture water

Abstract

The present invention discloses a device and method for deeply removing suspended matter from circulating aquaculture water, relating to the field of water treatment. The device comprises a breeding pond and a filter tank, wherein a fiber rotary disc filter is provided in the filter tank, and the water inlet of the filter tank is connected to the drain outlet at the bottom of the breeding pond via a pipe, on which a control valve is provided. The water outlet of the filter tank is connected to a temporary storage tank, which is connected to the breeding pond via a return pipe. The filter tank is connected to a magnetic coagulation sedimentation device via a sewage pump, and the clean water outlet of the magnetic coagulation sedimentation device is connected to the temporary storage tank via a clean water pipe, and the return pipe is provided with a water pump. A mud discharge device is provided in the filter tank. Based on the working method of the above-mentioned device, the present invention deeply removes suspended matter while avoiding the loss of aquaculture water by returning the water from which suspended matter has been removed to the breeding pond.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, in particular to a device and method for deeply removing suspended matter in circulating aquaculture water. Background Art

[0002] Aquaculture is a vital component of my country's food security system, providing a vast supply of high-quality animal-based protein. However, with the rapid development of my country's aquaculture industry, environmental degradation caused by wastewater is increasing, leading to frequent outbreaks of diseases in aquaculture organisms, compromising the sanitation and safety of aquatic products, and hindering the sustainable development of aquaculture. Recirculating aquaculture, characterized by its water conservation, high stocking density, controllable system, and resistance to external environmental influences, has become an inevitable trend in the development of the aquaculture industry. During the aquaculture water circulation process, high flow rates and high volume flow are achieved, resulting in extremely low suspended solids content, representing only a few ten-thousandths of the total water mass. Suspended solids primarily consist of feces, leftover bait, microalgae, and bacteria, ranging in size from centimeters to nanometers. If not promptly removed, these suspended solids will become even smaller or even dissolved. The effectiveness of suspended solids removal in the circulating water directly impacts the success of a recirculating aquaculture system. Current suspended solids treatment devices for recirculating aquaculture (RCA) suffer from low filtration accuracy and ineffectiveness. Commonly used vertical flow precipitators and rotary drum microfiltration systems can only remove suspended solids larger than 30 microns, while foam separators can only collect a portion of surface-active suspended solids. Furthermore, these devices require significant water flow to remove suspended solids from the aquaculture system. This significant water loss inevitably impacts the operational stability and economic viability of the RCA system. Summary of the Invention

[0003] The purpose of the present invention is to provide a device and method for deep removal of suspended matter in circulating aquaculture water to solve the problems existing in the above-mentioned prior art. By returning the water from which suspended matter has been removed to the aquaculture pond, the suspended matter can be deeply removed while avoiding the loss of aquaculture water.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a device for deeply removing suspended matter in circulating aquaculture water, comprising a breeding pond and a filter pond, wherein a fiber rotary disc filter is provided in the filter pond, a water inlet of the filter pond is connected to a drain outlet at the bottom of the breeding pond via a pipe, and a control valve is provided on the pipe; a water outlet of the filter pond is connected to a temporary storage tank, and the temporary storage tank is connected to the breeding pond via a return pipe, the filter pond is connected to a magnetic coagulation sedimentation device via a sewage pump, and a clean water outlet of the magnetic coagulation sedimentation device is connected to the temporary storage tank via a clean water pipe, and clean water flows into the temporary storage tank under the action of gravity; the fiber rotary disc filter is provided with a backwashing system, and the backwashing system is used to perform targeted backwashing on the filter cloth; a mud discharge device is provided in the filter pond.

[0006] Optionally, the fiber rotary disc filter includes a central drum, a filter disc, a transmission system and a matching electrical control system. The filter disc is fixed on the outside of the central drum and is connected to the central drum; the central drum is connected to the transmission system.

[0007] Optionally, the filter disc includes a frame and a filter cloth, wherein the filter cloth is wrapped on the frame, and the filter cloth is composed of a substrate woven from polyester and 1 to 2 cm thick pile woven from nylon fibers, and the pile is perpendicular to the substrate.

[0008] Optionally, the primary coagulation reaction tank, secondary coagulation reaction tank, flocculation reaction tank and clarification tank of the magnetic coagulation sedimentation device are connected in sequence, and the water flow can be coagulated and flocculated in these reaction tanks in sequence, and the final clean water flows out through the clean water outlet of the clarification tank. The sewage outlet of the filter tank is connected to the primary coagulation reaction tank, and the clean water outlet of the clarification tank is connected to the temporary storage tank. The magnetic seed-containing sludge discharged from the bottom of the clarification tank passes through the magnetic seed recovery device, and the recovered magnetic seeds enter the secondary coagulation reaction tank. The sludge flows to the sludge tank by gravity, and then a small amount of biological flocculant is added to the sludge tank for treatment, and the sludge is separated and treated by a centrifuge.

[0009] Optionally, an ozone disinfection device is also included; the ozone disinfection device is an ozone generator equipped with an ejector, and the ozone disinfection device is located at the front end of the water inlet of the primary coagulation reaction tank.

[0010] Optionally, an ultraviolet disinfection device is further included, which includes an ultraviolet sterilizer located at the side of the purified water outlet, and a plurality of ultraviolet lamps are arranged in the ultraviolet sterilizer, and the power of the ultraviolet lamps is 50-100w.

[0011] Optionally, the filtration accuracy of the filter cloth is not less than 10 microns and not more than 30 microns.

[0012] The present invention also provides a method for deep removal of suspended matter in circulating aquaculture water, comprising the following steps:

[0013] After the cultured organisms eat, the suspended solids concentration in the culture pond rises rapidly. The pre-cultured microalgae are artificially added to the culture pond at one time to make the algae density in the culture pond 1-10 mg / L.

[0014] After the microalgae and suspended solids have fully reacted, the aquaculture water flows into the filtration tank by gravity, is filtered through the fiber rotary filter, and the filtered clean water flows into the temporary storage tank and returns to the aquaculture tank through the water inlet pipe;

[0015] During the filtration process, pollutants accumulate. When the liquid level in the filter tank reaches the set value, the backwash system automatically starts to backwash out the impurities accumulated on the filter cloth;

[0016] The impurity-containing sewage from backwash enters the magnetic coagulation sedimentation device through the sewage outlet of the filter tank for treatment. The treated clean water flows into the temporary storage tank through the clean water pipe and finally returns to the breeding pond. The sludge without magnetic seeds after the magnetic seeds are recovered enters the sludge tank for temporary storage, and after treatment with a small amount of biological flocculant, it is separated and treated by a centrifuge.

[0017] Optionally, the microalgae are one or more of Euglena, Chlorella, Dunaliella salina, and Pseudomonas aeruginosa.

[0018] Compared with the prior art, the present invention has achieved the following technical effects:

[0019] In the present invention, after the cultured organisms eat, the suspended matter concentration in the culture pond rises rapidly. The micron-sized microalgae can act as nucleation centers or bioflocculants to promote the agglomeration of small-particle suspended matter and large-particle suspended matter, and the surface of the microalgae cells can quickly adsorb ammonia nitrogen dissolved in water, and then flow into the filter pool by gravity. The fiber rotary filter can not only filter, but also has a sedimentation function. Suspended matter with larger particle sizes sinks directly to the bottom, significantly reducing the amount of sludge on the filter cloth and greatly reducing the amount of backwash water. The present invention can efficiently remove more than 99% of suspended matter in the aquaculture tail water within two hours. When the filter cloth precision of the fiber rotary filter is 30μm, the total solid content of the treated water is less than 5mg / L. When the filter cloth precision is 10μm, the total solid content is less than 2mg / L, which is lower than the total solid content requirement of the fishery water quality standard. In this invention, the timely removal of suspended solids prevents them from becoming smaller and soluble components from dissolving. The treated aquaculture water is returned to the aquaculture pond via a return pipe. During the suspended solids removal process, water loss in 24 hours is less than 0.5% of the total aquaculture water volume. 99.5% of the aquaculture water is reused, eliminating the difficulty in regulating water temperature caused by adding new water. In this invention, the cost of treating 100 tons of aquaculture circulating water is less than 20 yuan. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a schematic diagram of the structural arrangement of a device for deep removal of suspended solids in circulating aquaculture water in Example 1 of the present invention;

[0022] Figure 2 Schematic diagram of the structural arrangement of the magnetic coagulation sedimentation device in Example 2 of the present invention;

[0023] Explanation of the accompanying numbers: 1-breeding pond, 2-filtration tank, 3-fiber rotary disc filter, 4-control valve, 5-temporary storage tank, 6-return pipe, 7-water pump, 8-transmission system, 9-magnetic coagulation sedimentation device, 901-clean water outlet, 902-primary coagulation reaction tank, 903-secondary coagulation reaction tank, 904-flocculation reaction tank, 905-clarification tank, 906-sludge tank, 10-glass fiber reinforced plastic grating. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] The purpose of the present invention is to provide a device and method for deep removal of suspended matter in circulating aquaculture water to solve the problems existing in the above-mentioned prior art. By returning the water from which suspended matter has been removed to the aquaculture pond, the suspended matter can be deeply removed while avoiding the loss of aquaculture water.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] The fiber rotary disc filter is a water treatment unit that is very effective in removing suspended solids. The total suspended solids in the effluent can be less than 2 mg / L, or even lower. The operating cost is also very low, and the operating cost of treating one ton of water is only 0.004 yuan. It has been widely used in sewage treatment, reclaimed water reuse, surface water purification and other fields.

[0029] Detailed research by the inventors revealed that the fiber rotary disc filter's sedimentation function significantly outperforms the vertical flow sedimentation devices commonly used in current recirculating aquaculture systems. Large suspended solids can be settled in a very short time and more easily discharged from the aquaculture system. Compared with rotary drum microfiltration, fiber rotary disc filters of the same filtration accuracy require less backwash water for suspended solids removal in recirculating aquaculture water. As the filter cloth's filtration accuracy increases, the backwash water volume increases accordingly. Interestingly, the inventors also discovered that the effective filter layer formed by the villi can intercept fine suspended solids by bridging. Can flocculants be used to pre-agglomerate fine suspended solids, and between fine and large suspended solids, so that fine suspended solids can be removed deeply through the effective filtration layer? The inventors' research found that common commercial flocculants, such as polyaluminum chloride and polyferric sulfate, are not suitable for deep removal of suspended solids in recirculating aquaculture water. This is primarily due to the long-term exposure of aquacultured organisms to an environment containing flocculants, significantly increasing the risk of food safety. In order to avoid the impact of flocculants on the food safety of farmed organisms, safe edible biological flocculants such as chitosan and microalgae extracellular polysaccharides are used. However, the experimental results of the system show that the actual effect is not very ideal, mainly because the biological flocculants are very easy to adhere to the substrate and fluff of the filter cloth, resulting in a significant increase in the backwash water volume.

[0030] Based on this, the inventors have designed and studied the use of microalgae as flocculants and combined them with fiber rotary disc filters to remove suspended solids in water. Figure 1 As shown, the structure of the deep removal device of suspended matter in the circulating aquaculture water of this embodiment includes a breeding pond 1 and a filter pond 2. A fiber rotary disc filter 3 is provided in the filter pond 2. The water inlet of the filter pond 2 is connected to the drain outlet at the bottom of the breeding pond 1 through a pipe, and a control valve 4 is provided on the pipe; the water outlet of the filter pond 2 is connected to the temporary storage tank 5, and the temporary storage tank 5 is connected to the breeding pond 1 through a return pipe 6, and a water pump 7 is provided on the return pipe 6; a mud discharge device is provided inside the filter pond 2.

[0031] The fiber disc filter consists of a central drum, filter discs, a drive system 8, a backwash system, and a supporting electrical control system. The filter discs are fixed to the outside of the central drum and connected to the central drum; the central drum is connected to the drive system. The filter disc consists of a frame and filter cloth. The frame is wrapped with the filter cloth. The filter cloth consists of a polyester backing and a 1-2 cm thick nylon fiber pile. The pile is perpendicular to the backing. The filter cloth has a filtration accuracy of no less than 10 microns and no more than 30 microns. During normal filtration, the pile collapses to form an effective filter layer 3-5 mm thick, effectively retaining large suspended solids. Clean water that passes through the filter cloth flows into the central drum and is discharged from the system through the central drum outlet. As filtration progresses, the amount of suspended solids trapped by the effective filter layer increases, and the amount of water passing through the filter cloth decreases. This causes the filter tank liquid level to rise and reach the set value, triggering the backwash system and transmission system. The backwash pump begins to operate, and the filter discs begin to rotate. Under the strong suction of the backwash pump, the clean water passing through the filter cloth washes the filter cloth substrate and the effective filter layer from the inside out, causing the effective filter layer to lose its effectiveness and return to a fluffy state. Suspended solids accumulated on the effective filter layer and on the outside are discharged into the sewage pipe with the backwash water and then discharged from the device. After the backwash is completed, the filter cloth forms an effective filter layer again, and static filtration begins. This cycle continues.

[0032] The working method of the device for deep removal of suspended solids in circulating aquaculture water in this embodiment includes the following steps:

[0033] After the cultured organisms have eaten, when the concentration of fine particles in the culture pond is high, for example, 30 to 60 minutes after the cultured organisms have eaten, a certain amount of pre-cultured microalgae is added at one time. The microalgae is one or more of the species Euglena, Chlorella, Dunaliella salina, and Pseudomonas salina, so that the algae density in the culture pond is 1 to 10 mg / L. Micron-sized microalgae can act as nucleation centers or flocculants to promote the aggregation of small suspended particles and large suspended particles; the surface of microalgae cells can quickly adsorb ammonia nitrogen dissolved in water;

[0034] After the microalgae and suspended solids have fully reacted, the control valve 4 on the drain pipe is opened to allow the aquaculture water to flow into the filter tank 2 by gravity. The control valve 4 can adjust the flow of the drain pipe as needed, and the filtered water flows into the temporary storage tank 5 through the fiber rotary filter 3, and returns to the aquaculture tank 1 through the return pipe 6. The water outlet of the fiber rotary filter 3 after filtration can directly enter the water inlet of the aquaculture tank 1 through the temporary storage tank 5, or it can be returned to the aquaculture tank after further purification. The sewage outlet of the fiber rotary filter 3 is connected to the sewage storage tank; the fiber rotary filter can not only filter, but also has a sedimentation function. Suspended solids with larger particle sizes sink directly to the bottom, which significantly reduces the amount of sludge on the filter cloth and greatly reduces the amount of backwash water. In the present invention, the fiber rotary filter can efficiently remove more than 99% of suspended solids in the aquaculture tail water within two hours;

[0035] During the filtration process, pollutants accumulate. When the liquid level in the filter tank reaches the set value, the backwash system automatically starts to backwash out the impurities accumulated on the inside of the filter cloth.

[0036] Example 2

[0037] Considering that when the fiber rotary filter 3 is backwashed, this part of the water mixes with the impurities backwashed away and cannot flow back into the breeding pond, which still causes a waste of part of the breeding water, the inventors uniquely designed a magnetic coagulation sedimentation device 9 in communication with the filter pond based on the first embodiment, such as Figure 2 As shown, the clean water outlet 901 of the magnetic coagulation sedimentation device 9 is connected to the temporary storage tank 5 through a clean water pipe, and a valve is provided on the clean water pipe. The magnetic coagulation sedimentation device 9 includes a primary coagulation reaction tank 902, a secondary coagulation reaction tank 903, a flocculation reaction tank 904, a sludge tank 906 and a clarification tank 905. The primary coagulation reaction tank 902, the secondary coagulation reaction tank 903, the flocculation reaction tank 904 and the clarification tank 905 are connected in sequence. The clean water outlet 901 is opened on one side of the clarification tank 905, and the filter tank 2 is connected to the primary coagulation reaction tank 902. After the magnetic seeds are recovered by the magnetic seed recoverer, the magnetic seeds enter the secondary coagulation reaction tank, and the sludge without magnetic seeds flows to the sludge tank by gravity, and then a small amount of biological flocculant is added to the sludge tank. After treatment, the sludge is concentrated and dehydrated by centrifugation. In one embodiment, a glass fiber reinforced plastic grating 10 is provided within the magnetic coagulation sedimentation device 9 for impurity filtering. The structure and position of the glass fiber reinforced plastic grating 10 are not specifically limited. To simplify the structure, the glass fiber reinforced plastic grating 10 may also be omitted. The magnetic coagulation sedimentation device 9 of the present invention adds magnetic seeds on top of conventional coagulation. The polyaluminum chloride, magnetic seeds, and anionic polyacrylamide used are all commercially available drinking water pretreatment agents. The clear water discharged from the clarifier is returned to the aquaculture pond. The magnetic seed recovery device discharges the sludge without magnetic seeds and centrifuges it. The supernatant enters the entrance of the clarifier. The resulting solids are disposed of in accordance with the relevant provisions of the solid waste management regulations, and the lost water is replenished with new water. During the coagulation process, a high concentration of magnetic seeds and some reflux sludge are always present. The magnetic seed-containing flocs formed by the flocculant, pollutants, magnetic seeds, and coagulant aid have a high specific gravity and a fast gravity settling rate.

[0038] The inventor tested the water in the aquaculture pond Al every day. 3+ and the concentration of polyacrylamide, Al 3+ The concentration of polyacrylamide hardly changes and is at a low level, which completely eliminates the Al 3+The concentration of polyacrylamide may increase, which may cause concerns about the safety of aquaculture organisms. In other words, the conventional magnetic coagulation and sedimentation process can be used for online purification of aquaculture circulating water. The inventors conducted detailed research and found that the solid content of the sludge discharged from the magnetic seed recovery device in the magnetic coagulation sedimentation process is only 0.5% to 2%. If solids that are easy to store and transport are to be obtained, the moisture content of the sludge must be lower than 75%. Cationic flocculants must be added before centrifugal separation. Once the cationic flocculant water flow enters the aquaculture water body, it will weaken the bonding and bridging effect of the anionic polyacrylamide. The effect of purifying the aquaculture circulating water by the magnetic coagulation sedimentation process will be affected to a certain extent, or even greatly reduced. Based on this, in order to increase the sludge flocs, the present invention can add a small amount (10% to 20% of the mass fraction of the coagulant, optimally 15%) of biological flocculants with opposite charge properties to the coagulant, such as purple algae extracellular polysaccharides and chitosan, into the sludge pool, thereby avoiding the problem of water containing cations affecting aquaculture. Centrifugal separation is preferentially used for concentration and dehydration, and the clear water enters the clarification tank of the magnetic coagulation sedimentation device. The obtained solids are harmlessly treated and then discharged. The magnetic coagulation and sedimentation device effectively removes large suspended solids from the fiber disc filter's sludge discharger, as well as smaller suspended solids such as bacteria and viruses from the backwasher. It also fully removes macromolecular proteins, oils, and other substances, producing solids with a moisture content of 70%-75%, without any wastewater discharge. The resulting solids can be used as organic fertilizer after treatment, with a treatment cost of approximately 0.30 yuan per ton of aquaculture water. After treatment, wastewater can be returned to the aquaculture pond or sent to a water purification process, particularly for deep purification of water-soluble nitrogen and phosphorus nutrients.

[0039] Further preferably, in another embodiment, an ozone disinfection device and an ultraviolet disinfection device can be additionally provided. The ozone disinfection device is preferably an ozone generator equipped with an ejector. The ozone disinfection device is preferably located at the front end of the water inlet of the magnetic coagulation sedimentation device. The water in the fiber rotary filter water body is treated by introducing ozone through the ejector. The ozone introduction rate is 15 to 25 g / h, preferably 18 to 22 g / h, and more preferably 20 g / h. An ultraviolet sterilizer is provided after the magnetic coagulation sedimentation device. Several ultraviolet lamps are provided in the ultraviolet sterilizer. The power of the ultraviolet lamp is preferably 50 to 100 w, and more preferably 75 w. The brand of the ultraviolet lamp can be selected from Philips. Disinfection of aquaculture water is more conducive to maintaining the water quality of aquaculture water and realizing the recycling of aquaculture water.

[0040] The working method of the device for deep removal of suspended solids in circulating aquaculture water in this embodiment includes the following steps:

[0041] After the cultured organisms eat, the suspended matter concentration in the culture pond 1 increases, and pre-cultured microalgae are artificially added to the culture pond 1 at one time to make the algae density in the culture pond 1 to be 1-10 mg / L;

[0042] After the microalgae and suspended matter are aggregated and flocculated to the bottom of the culture pond 1, the control valve 4 on the drain pipe is opened to allow the aggregated and flocculated suspended matter to flow into the filter tank, and then the fiber rotary disc filter is opened for filtration. During the operation of the fiber rotary disc filter 3, water flows into the drum from the opening at one end of the central drum, enters each rotary disc through the connecting hole, and after being filtered through the filter cloth, the clean water flows out of the filter cloth and flows out from the filtered water outlet. In the present invention, as the filtration proceeds, the pollutants trapped on the inside of the filter cloth continue to increase, the filtration pressure difference increases accordingly, and the amount of water that successfully passes through the filter cloth decreases. The filtered clean water flows into the temporary storage tank 5 and returns to the culture pond 1 through the return pipe;

[0043] When pollutants accumulate to a certain level and the filter tank liquid level reaches the set value, backwashing is performed to backwash out the impurities accumulated inside the filter cloth. The backwash water pump draws clean water that has passed through the filter cloth and sprays it onto the outside of the filter cloth, washing away the trapped impurities inside the filter cloth. After washing, the sewage enters the magnetic coagulation and sedimentation device. During backwashing, the turntable rotates, and the backwash water sprays the filter cloth at different angles until the turntable rotates one circle and the filter cloth is completely cleaned. The backwash stops and the filtration process re-enters until backwashing is performed again.

[0044] The backwashed wastewater containing impurities flows into the magnetic coagulation sedimentation device 9 through the sewage outlet of the filter tank for secondary disinfection, flocculation and sedimentation treatment. The clean water after secondary treatment flows into the temporary storage tank through the clean water pipe and finally flows back to the breeding pond.

[0045] In the description of the present invention, it should be noted that the terms "center," "top," "bottom," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for deep removal of suspended matter in circulating aquaculture water based on a device for deep removal of suspended matter in circulating aquaculture water, characterized in that: The device for deeply removing suspended matter in circulating aquaculture water comprises a breeding pond and a filter pond, wherein a fiber rotary disc filter is provided in the filter pond, and the water inlet of the filter pond is connected to the drain outlet at the bottom of the breeding pond via a pipe, and a control valve is provided on the pipe; the water outlet of the filter pond is connected to a temporary storage tank, and the temporary storage tank is connected to the breeding pond via a return pipe, and the filter pond is connected to a magnetic coagulation sedimentation device via a sewage pump, and the clean water outlet of the magnetic coagulation sedimentation device is connected to the temporary storage tank via a clean water pipe, and a water pump is provided on the return pipe; and a mud discharge device is provided in the filter pond; The fiber rotary disc filter includes a central drum, a filter disc, a transmission system, a backwash system and a supporting electrical control system. The filter disc is fixed on the outside of the central drum and is connected to the central drum; the central drum is connected to the transmission system; The filter disc includes a frame and a filter cloth, wherein the frame is wrapped with the filter cloth, and the filter cloth is composed of a polyester woven substrate and nylon fiber woven into a 1 to 2 cm thick pile, and the pile is perpendicular to the substrate; The primary coagulation reaction tank, secondary coagulation reaction tank, flocculation reaction tank and clarification tank of the magnetic coagulation sedimentation device are connected in sequence, the clean water outlet is opened on one side of the clarification tank, the filter tank is connected to the primary coagulation reaction tank, the clean water outlet of the clarification tank is connected to the temporary storage tank, the magnetic seed-containing sludge discharged from the bottom of the clarification tank passes through the magnetic seed recovery device, and the recovered magnetic seeds enter the secondary coagulation reaction tank, and the sludge flows into the sludge tank by gravity; The filtration accuracy of the filter cloth is not less than 10 microns and not more than 30 microns; The method for deep removal of suspended matter in circulating aquaculture water comprises the following steps: After the cultured organisms eat, the suspended solids concentration in the culture pond rises rapidly. The pre-cultured microalgae are artificially added to the culture pond at one time to make the algae density in the culture pond 1-10 mg / L. After the microalgae and suspended solids have fully reacted, the control valve on the drain pipe is opened, and the aquaculture water flows into the filter tank by gravity, is filtered by the fiber rotary filter, and the filtered clean water flows into the temporary storage tank and returns to the aquaculture tank through the return pipe; During the filtration process, pollutants accumulate. When the liquid level in the filter tank reaches the set value, the backwash system automatically starts to backwash out the impurities accumulated on the filter cloth; The backwashed wastewater containing impurities enters the magnetic coagulation sedimentation device through the sewage outlet of the filter tank for treatment. The treated clean water flows into the temporary storage tank through the clean water pipe and finally returns to the breeding pond.

2. The method for deep removal of suspended solids in circulating aquaculture water according to claim 1, characterized in that: It also includes an ozone disinfection device; the ozone disinfection device is an ozone generator equipped with an ejector, and the ozone disinfection device is located at the front end of the water inlet of the primary coagulation reaction tank.

3. The method for deep removal of suspended solids in circulating aquaculture water according to claim 1, characterized in that: It also includes an ultraviolet disinfection device, which includes an ultraviolet sterilizer located at the side of the purified water outlet. A plurality of ultraviolet lamps are arranged in the ultraviolet sterilizer, and the power of the ultraviolet lamps is 50-100w.

4. The method for deep removal of suspended solids in circulating aquaculture water according to claim 1, characterized in that: The microalgae are one or more of Euglena, Chlorella, Dunaliella salina, and Pseudomonas aeruginosa.

Images