A recirculating water rearing system

Abstract

The utility model relates to the technical field of mud crab breeding, more particularly to a circulating water breeding system, including the aquaculture pond, biochemical water purification module and the rough pond, the aquaculture pond with biochemical water purification module and the rough pond intercommunication, the aquaculture pond can breed the conchoecidiform larva crab seed, the biochemical water purification module can remove ammonia and nitrogen in the water body of the aquaculture pond through nitrification bacteria and algae, and then the purified water body is re - inputed into the aquaculture pond, the rough pond can hide for the crab seed. The utility model discloses a breeding system can purify water quality, keep the stable water quality in the pool, and can also transfer the mud crab into the rough pond to grow into the large -eye larva, so that the crab seed has wider living space in the rough pond and can hide, reduces the loss of cannibalism, and further solves the low yield and unstable yield of mud crab artificial breeding in the prior art, improves the yield of crab seed and increases the income.

Description

Technical Field

[0001] This utility model relates to the technical field of mud crab seedling cultivation, and more specifically, to a recirculating water seedling cultivation system. Background Technology

[0002] Mud crabs are a traditional export aquatic product and an important aquaculture species in my country. However, due to the low and unstable yield of artificially cultivated crab seedlings, the mud crab seedlings currently circulating in the market are still mainly wild seedlings caught in the sea.

[0003] The low yield and more unstable production of artificially bred crab seedlings compared to wild-caught seedlings are due to the fact that artificial breeding of mud crabs mostly adopts indoor factory-style breeding methods. The small water space and high seedling density lead to higher nitrate and ammonia levels in the water, making the crab seedlings more susceptible to disease and even death. Furthermore, as a ferocious carnivorous crab, mud crabs are highly susceptible to cannibalism after metamorphosing from zoea larvae to megalopa larvae and developing claws. The megalopa larvae, which metamorphose early, will prey on the later-metamorphosing zoea larvae. Therefore, even if artificially bred seedlings successfully reach the megalopa larval stage, the subsequent cannibalism often leaves very few seedlings alive. Utility Model Content

[0004] The purpose of this invention is to overcome the low and unstable crab seedling yield in the existing technology when artificially raising mud crabs, and to provide a recirculating water seedling raising system. The recirculating water seedling raising system of this solution can not only increase the yield when artificially raising crabs, but also make the crab seedling yield more stable.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A recirculating aquaculture system is provided, characterized in that it includes a breeding pond, a biochemical water purification module, and a nursery pond, wherein the breeding pond is connected to the biochemical water purification module and the nursery pond; The breeding pond can raise zoea larvae; the biochemical water purification module can remove ammonia and nitrogen from the water in the breeding pond through nitrification by bacteria and algae before the purified water is reintroduced into the breeding pond; the mud in the standard breeding pond can provide hiding places for the larvae.

[0006] This utility model's recirculating aquaculture system allows for the rearing and cultivation of zoea larvae of mud crabs in a rearing pond. The biochemical water purification module purifies the water in the pond, using nitrifying bacteria and algae to treat excess ammonia nitrogen. After purification, the water can be reintroduced into the rearing pond, creating a water cycle. The growth period for zoea larvae of mud crabs is approximately 30 days. Most zoea larvae introduced into the pond at the same time enter the megalopa stage. Once about half of the larvae in the rearing pond have entered the megalopa stage, they are transferred to a nursery pond. This means the rearing period for zoea larvae in the rearing pond is approximately 30 days. The larvae transferred to the nursery pond are mostly just entering or about to enter the megalopa stage; at this stage, cannibalism has not yet caused significant losses. After transferring crab larvae to the nursery pond, which is larger and has deeper mud than the rearing pond, the larvae can hide in the mud. This increased hiding place further reduces larval losses. Most zoea larvae will enter the megaloblast stage within 1-2 days after hiding in the nursery pond, preventing cannibalism.

[0007] The nursery pond, also known as the pre-nurturing pond, is surrounded by netting to prevent crab larvae from escaping. The pond bottom has a mud layer thick enough for the larvae to hide in. The nursery pond also allows for water circulation to maintain water quality suitable for the larvae's growth. Generally, the density of crab larvae in the rearing pond is 500-1500 times that in the nursery pond. The specific density ratio is dynamically adjusted based on ecological carrying capacity, growth space requirements, larvae characteristics, facility conditions, and target size.

[0008] In addition, seedling net cages containing daphnia larvae can be placed in the breeding pond. When most of the larvae in the net cages have grown into megalopa larvae, they can be released into the breeding pond. Then, the larvae in the breeding pond can be transferred to the nursery pond by changing the water.

[0009] This invention's seedling system, through the connection of a biochemical water purification module and a nursery pond to the rearing pond, not only purifies the water and maintains stable water quality within the pond, reducing the risk of disease in zoea larvae of crabs in the rearing pond, but also allows crabs that have grown into megalopa larvae to be transferred to the nursery pond. The crab seedlings have a wider living space and can hide in the nursery pond, reducing cannibalistic losses. This solves the problems of low and unstable yields in existing artificial breeding techniques for mud crabs, increasing the yield of crab seedlings and thus increasing income.

[0010] Furthermore, the biochemical water purification module includes a biochemical water purification tank and a biochemical water purification container; The biochemical water purification tank is connected to the aquaculture tank. The bottom of the biochemical water purification tank is covered with activated sludge, and the biochemical water purification tank contains algae that can perform nitrification. The bottom of the biochemical water purification tank is connected to the biochemical water purification pool, and the top of the biochemical water purification tank is connected to the water inlet of the aquaculture pool. The biochemical water purification tank is equipped with biochemical bacteria. The water in the biochemical water purification tank can flow into the aquaculture pond along the biochemical water purification box.

[0011] The biological water purification module includes a purification tank and a purification vessel. The purification tank uses activated sludge and algae to initially purify the water entering from the breeding pond, reducing the ammonia nitrogen content. After initial purification in the purification tank, the water enters the purification vessel, where biochemical bacteria further purify the water, further reducing the ammonia nitrogen content and ensuring the water quality meets the growth requirements of crab larvae. The biochemical bacteria include nitrifying bacteria, which oxidize ammonia to nitrite, and further to nitrate, thus reducing the ammonia content. Activated sludge and algae can coexist, jointly removing ammonia nitrogen from the water. Placing the biochemical bacteria and algae separately in the purification tank and purification pool further improves their purification efficiency.

[0012] Furthermore, a partition is fixedly installed inside the biochemical water purification tank, which divides the biochemical water purification tank into a top cavity and a bottom cavity, and the partition has a plurality of water-permeable holes arranged in an array. The top of the top cavity is connected to the water inlet of the aquaculture pond, and the biochemical bacteria are located inside the top cavity; The bottom cavity and the biochemical water purification tank are connected by an inlet pipe, and a water pump is connected to one end of the inlet pipe located inside the biochemical water purification tank.

[0013] The water pump, once installed, transfers water from the biological purification tank to the biological purification chamber. The chamber has water inlet at the bottom and outlet at the top, extending the water's residence time and improving the purification effect of the biological bacteria. The baffles prevent water from directly impacting the bacteria and also prevent bacterial colonies from clogging the chamber's inlet.

[0014] Furthermore, the biochemical water purification tank is equipped with a growth plate for algae to attach to, and the growth plate is fixedly installed at one end of the biochemical water purification tank away from the bottom surface. The growth plate facilitates the attachment of algae during their growth process, providing more growth space for the algae and resulting in a greater quantity of algae in the tank, thus improving the purification effect on the water.

[0015] Furthermore, it also includes an air pump, a first aeration section, and a second aeration section. The air outlet of the air pump is connected to the first aeration section via a first air pipe, and the air pump is connected to the second aeration section via a second air pipe. The first aeration section is fixedly installed in the bottom cavity, and the second aeration section is located inside the biological water purification tank and is closer to the bottom surface of the biological water purification tank than the growth plate. The air pump can pump air into the biological water purification tank and the biological water purification chamber, allowing algae and biochemical bacteria to carry out nitrification in an aerobic environment. At the same time, the gas pumped in can also strip ammonia nitrogen from the water, and the escaping gas can carry away ammonia nitrogen in the water, further reducing the ammonia nitrogen content in the water.

[0016] Furthermore, it also includes a third aeration unit, which is connected to the air outlet of the air pump via a third air pipe. The third aeration unit is fixedly installed on the bottom surface of the aquaculture pond. The third aeration unit can oxygenate the aquaculture pond. The air outlet of the air pump is equipped with a three-inlet / three-outlet pipe connector. The inlet end of the connector is connected to the outlet end of the air pump, and the three outlet ends of the connector are respectively connected to the first air pipe, the second air pipe, and the third air pipe. The first, second, and third aeration units can all be aeration discs or aeration pipes.

[0017] Furthermore, the water pump inlet is equipped with a baffle, which is detachably connected to the water pump inlet. The baffle prevents algae and sludge in the biological water purification tank from clogging the water pump inlet. A water pipe is connected to the water pump inlet, which is also the inlet of the water pipe. The water pipe is located at the bottom of the biological water purification tank, and the baffle is detachably installed at the inlet of the water pipe. The baffle can be threaded, snap-fitted, or directly placed over the inlet of the water pipe.

[0018] Furthermore, the bottom of the aquaculture pond is conical, and a drain outlet is provided at the apex of the conical bottom. The drain outlet is equipped with a drain valve and a drain pipe. The drain valve is located at the inlet end of the drain pipe. The drain pipe is also equipped with a first valve, a second valve, and a third valve. The first valve is connected to the inlet end of the biological water purification tank; the second valve is connected to the inlet end of the pre-fertilization pond; and the third valve can be connected to the inlet end of the sewage discharge tank. The bottom of the aquaculture pond is conical, with the apex of the conical bottom being the lowest point of the aquaculture pond in the vertical direction. The conical bottom surface of the aquaculture pond is preferably conical, but it can also be spherical. The conical bottom of the aquaculture pond facilitates the discharge of water from the pond through the drain outlet. The outlet end of the drain pipe has three branch pipes, which are respectively connected to the biological water purification tank, the pre-fertilization pond, and the sewage discharge tank. Three valves are installed on the three branch pipes respectively. When the drain valve and the first valve are open and the other valves are closed, the water in the breeding pond flows into the biological purification pond along the drain pipe. When the drain valve and the second valve are open and the other valves are closed, the water in the breeding pond, carrying crab larvae, flows into the nursery pond along the drain pipe. When the drain valve and the third valve are open and the other valves are closed, the water in the breeding pond flows into the sewage pond along the drain pipe. Since some water is discharged along with sludge during sewage discharge, the breeding pond is generally sludge-discharged before water exchange, and this is usually done frequently and for short periods. This minimizes disturbance to the aquatic environment, especially when the crab larvae density is high, reducing stress on the larvae. To prevent larvae from escaping, farmers install escape-proof nets (which can be net bags, net sheets, or net cages that can be installed or fixed at the drain outlet) at the sewage discharge or water exchange. The mesh of the escape-proof net allows sludge or water to pass through while preventing the larvae from escaping. For zoea larvae, 120-mesh or higher mesh escape-proof nets are generally required. When too many crab larvae adhere to the escape-proof net, temporarily close the drain valve, gently lower the net into the water and shake it to allow the larvae to detach before continuing. When the escape-proof net becomes clogged with mud, temporarily close the drain valve and replace it with a new one. When opening the second valve to transfer the crab larvae, they can enter the nursery pond along with the water through the drain pipe.

[0019] Furthermore, the breeding pond is also equipped with a berried sand tray for mud crab seedlings to carry their eggs. The berried sand tray is movably installed within the breeding pond. The berried sand tray simulates the natural living environment of mud crab seedlings. It includes a sand tray frame filled with fine sand for the seedlings to carry their eggs. A support frame, shaped like an "A," is located at the bottom of one end of the frame. The length of the "A"-shaped support frame is adjustable to change the height of the frame, and it can rotate to accommodate different pond bottom structures. A hanging rope is located at the top of the frame opposite the support frame, and the rope can be secured via hooks on the side wall or top of the breeding pond. The berried sand tray in the breeding pond allows it to be used for carrying eggs of mud crab seedlings when not raising zoea larvae, thus improving the utilization rate of the breeding pond.

[0020] Furthermore, the drain valve includes a sleeve installed on the drain outlet. An outer tube is detachably connected to the outer ring of the sleeve, and an inner tube is detachably connected to the inner ring of the sleeve. An inlet is located at the bottom of the outer tube, and an overflow outlet is located on the side wall of the inner tube. The sleeve has a convex cross-section, including an outer platform with a larger diameter and an inner platform with a smaller diameter. The inner platform is located above the outer platform, and a through hole for connecting the drain outlet is located at the center of the inner platform. The bottom of the inner wall of the outer tube is threaded to the outer wall of the outer platform; the bottom of the inner wall of the inner tube is threaded to the outer wall of the inner platform. The inlet allows water and sludge to pass through while preventing crabs from passing through. There are multiple inlets, arranged equidistantly in a circle around the axis of the outer tube. There are also multiple overflow outlets, arranged equidistantly in a circle around the axis of the inner tube. The length of the inner tube is not less than the length of the outer tube, allowing the aquaculture personnel to rotate the inner tube smoothly. When the inner pipe is separated from the sleeve, water in the aquaculture pond can enter the drain pipe through the inlet on the outer pipe for sewage discharge and water exchange. When both the inner and outer pipes are separated from the sleeve, the entire aquaculture pond can be quickly cleaned and its water replaced. The water level in the aquaculture pond is determined by the height of the overflow outlet on the inner pipe, and the water level in the pond must never exceed the overflow outlet. When the aquaculture pond is used for breeding crabs carrying eggs, the drain valve, with its inner and outer pipes, eliminates the need for an escape-proof net at the drain outlet.

[0021] Compared with the prior art, the beneficial effects of this utility model are: This utility model's recirculating water seedling system, through the connection of a biochemical water purification module and a nursery pond to the breeding pond, not only purifies the water quality and maintains stability within the pond, reducing the risk of disease in zoea larvae of crabs in the breeding pond, but also allows crabs that have grown into megalopa larvae to be transferred to the nursery pond. The crab seedlings have a wider living space and can hide in the nursery pond, reducing losses due to cannibalism. This solves the problems of low and unstable yields in existing artificial breeding of mud crabs, increasing the yield of crab seedlings and thus increasing income.

[0022] The recirculating water seedling system of this invention also allows the breeding pond to be used for brooding crab seedlings when not raising zoea larvae, by setting up an egg-bearing sand tray in the breeding pond, thereby improving the utilization rate of the breeding pond. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a recirculating water seedling system; Figure 2 This is a schematic diagram of the structure inside a breeding pond in a recirculating aquaculture system. Figure 3 A schematic diagram of the structure of a biochemical water purification module in a recirculating water seedling system; Figure 4 This is a schematic diagram of the structure of a third embodiment of a recirculating water seedling system; Figure 5 A schematic diagram of the structure of an egg-bearing sand tray in a recirculating water seedling system; Figure 6 This is a schematic diagram of the drainage valve in a third embodiment of a recirculating water seedling system.

[0024] In the attached diagram: 100, aquaculture pond; 200, biochemical water purification module; 300, pre-breeding pond; 210, biochemical water purification tank; 220, biochemical water purification container; 230, activated sludge; 240, algae; 250, biochemical bacteria; 211, growth plate; 221, partition; 260, inlet pipe; 270, water pump; 400, air pump; 410, first aeration section; 420, second aeration section; 430, third aeration section. Part; 411, First air pipe; 421, Second air pipe; 431, Third air pipe; 500, Drain valve; 600, Drain pipe; 610, First valve; 620, Second valve; 630, Third valve; 700, Incubated sand tray; 510, Sleeve; 520, Inner pipe; 530, Outer pipe; 521, Overflow outlet; 531, Inlet; 710, Sand tray frame; 720, Leg frame; 730, Suspension rope. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0026] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0027] Example 1 This embodiment is a first embodiment of a recirculating water seedling raising system, including a breeding pond 100, a biochemical water purification module 200 and a nursery pond 300, wherein the breeding pond 100 is connected to the biochemical water purification module 200 and the nursery pond 300. The breeding pond 100 can raise zoea larvae; the biochemical water purification module 200 can remove ammonia and nitrogen from the water in the breeding pond 100 through nitrification by bacteria and algae before the purified water is reintroduced into the breeding pond 100; the pre-breeding pond 300 can provide hiding places for megalopa larvae.

[0028] Specifically, a 300-meter-wide nursery pond is a type of nursery where the crab larvae are enclosed by netting to prevent escape. The mud at the bottom is thick enough to provide hiding places for the larvae. The nursery pond also allows for water circulation to maintain water quality that meets the growth needs of the larvae. Generally, the density of crab larvae in a 100-meter-wide rearing pond is 500-1500 times that in a 300-meter-wide nursery pond. The specific density ratio is dynamically adjusted based on ecological carrying capacity, growth space requirements, larvae characteristics, facility conditions, and target size.

[0029] The working principle or process of this embodiment is as follows: When the recirculating aquaculture system is in operation, zoea larvae of mud crabs can be raised in the rearing pond 100. The biochemical water purification module 200 purifies the water in the rearing pond 100, using nitrifying bacteria and algae to treat excess ammonia nitrogen. After purification, the biochemical water purification tank 210 can reintroduce the purified water into the rearing pond 100, forming a water cycle. The growth period of zoea larvae of mud crabs is approximately 30 days. Most zoea larvae entering the pond at the same time enter the megalopa stage at roughly the same time. Once half of the crab larvae in the rearing pond 100 have entered the megalopa stage, they are transferred to the nursery pond 300. Therefore, the rearing time for zoea larvae in the rearing pond 100 is approximately 30 days. Most of the crab larvae entering the nursery pond 300 are just entering or about to enter the megalopa stage, at which point cannibalism has not yet caused significant losses. After transferring the crab larvae to the nursery pond (300 sq m), the area of ​​the nursery pond is larger than that of the rearing pond (100 sq m), and the mud in the nursery pond is deeper, allowing the crab larvae to hide in the mud. More hiding places further reduce larvae loss. After hiding in the nursery pond, most of the zoea larvae will enter the megaloblast stage within 1-2 days, preventing death due to cannibalism.

[0030] The beneficial effects of this embodiment are as follows: The seedling system of this embodiment connects the biochemical water purification module 200 and the nursery pond 300 to the breeding pond 100. This not only purifies the water and maintains stable water quality in the pond, reducing the risk of disease in the zoea larvae of crab seedlings in the breeding pond 100, but also allows the crabs that have grown into megalopa larvae to be transferred to the nursery pond 300. The crab seedlings have a wider living space in the nursery pond 300 and can hide, reducing losses from cannibalism. This solves the problem of low and unstable yield in artificial breeding of crabs in the prior art, increases the yield of crab seedlings, and increases income.

[0031] Example 2 This embodiment is a second embodiment of a recirculating water seedling system. Based on the first embodiment, this embodiment further defines the system.

[0032] Specifically, the biochemical water purification module 200 includes a biochemical water purification tank 210 and a biochemical water purification container 220; The biological water purification tank 210 is connected to the breeding tank 100. The bottom of the biological water purification tank 210 is covered with activated sludge 230, and the biological water purification tank 210 contains algae 240 that can carry out nitrification. The bottom of the biochemical water purification tank 220 is connected to the biochemical water purification pool 210, and the top of the biochemical water purification tank 220 is connected to the water inlet of the breeding pool 100. The biochemical water purification tank 220 is equipped with biochemical bacteria 250. The water in the biochemical water purification tank 210 can flow into the breeding pond 100 along the biochemical water purification box 220.

[0033] Specifically, the biochemical water purification tank 210 is equipped with a growth plate 211 for algae 240 to attach to, and the growth plate 211 is fixedly installed at one end of the biochemical water purification tank 210 away from the bottom surface of the biochemical water purification tank 210.

[0034] Specifically, a partition 221 is fixedly installed inside the biochemical water purification tank 220. The partition 221 divides the biochemical water purification tank 220 into a top cavity and a bottom cavity. Several water-permeable holes are arrayed on the partition 221. The top of the top cavity is connected to the water inlet of the aquaculture tank 100, and the biochemical bacteria 250 are located inside the top cavity; The bottom cavity and the biochemical water purification tank 210 are connected by an inlet pipe 260, and a water pump 270 is connected to one end of the inlet pipe 260 located inside the biochemical water purification tank 210.

[0035] Specifically, the water pump 270 has a screen at its inlet 531, which is detachably connected to the inlet 531. A water pipe is connected to the inlet of the water pump 270, and the inlet 531 of the water pump 270 is the inlet of the water pipe. The water pipe is located at the bottom of the biological water purification tank 210, and the screen is detachably installed at the inlet of the water pipe. The screen can be threaded, snap-fitted, or directly placed over the inlet of the water pipe.

[0036] Specifically, it also includes an air pump 400, a first aeration section 410 and a second aeration section 420. The air outlet of the air pump 400 is connected to the first aeration section 410 through a first air pipe 411, and the air pump 400 is connected to the second aeration section 420 through a second air pipe 421. The first aeration section 410 is fixedly installed in the bottom cavity, and the second aeration section 420 is located inside the biochemical water purification tank 210 and the second aeration section 420 is closer to the bottom surface of the biochemical water purification tank 210 than the growth plate 211.

[0037] Specifically, it also includes a third aeration unit 430, which is connected to the air outlet of the air pump 400 via a third air pipe 431. The third aeration unit 430 is fixedly installed on the bottom surface of the aquaculture pond 100. The air outlet of the air pump 400 is equipped with a three-inlet / three-outlet pipe connector. The inlet end of the connector connects to the outlet end of the air pump 400, and the three outlet ends of the connector connect to the first air pipe 411, the second air pipe 421, and the third air pipe 431, respectively. The first aeration unit 410, the second aeration unit 420, and the third aeration unit 430 can all be aeration discs or aeration pipes.

[0038] Specifically, the bottom of the aquaculture pond 100 is conical, and a drain outlet is provided at the pointed end of the conical bottom of the aquaculture pond 100. The drain outlet is equipped with a drain valve 500 and a drain pipe 600. The drain valve 500 is located at the water inlet end of the drain pipe 600. The drain pipe 600 is also equipped with a first valve 610, a second valve 620 and a third valve 630. The first valve 610 is connected to the water inlet end of the biological purification pond 210; the second valve 620 is connected to the water inlet end of the standard breeding pond 300; and the third valve 630 can be connected to the water inlet end of the sewage discharge pond.

[0039] Specifically, an escape-proof net (which can be a net bag, net sheet, or net box that can be installed or fixed at the drain outlet) will be installed at the drain outlet. The mesh of the escape-proof net can allow mud or water to pass through while preventing crab larvae from passing through. For zoea larvae, an escape-proof net of 120 mesh or higher is generally required.

[0040] The working principle or process of this embodiment is as follows: When drain valve 500 and the first valve 610 are open and the other valves are closed, the water in the breeding pond 100 flows into the biological purification pond 210 along the drain pipe 600; when drain valve 500 and the second valve 620 are open and the other valves are closed, the water in the breeding pond 100, carrying crab larvae, flows into the nursery pond 300 along the drain pipe 600; when drain valve 500 and the third valve 630 are open and the other valves are closed, the water in the breeding pond 100 flows into the sewage pond along the drain pipe 600. Since some water is discharged along with sludge when the breeding pond 100 is sludged, the breeding pond 100 is generally sludged first and then the water is changed. Furthermore, sludge discharge or water change is usually performed frequently and for short periods, which minimizes disturbance to the aquatic environment, especially when the density of crab larvae in the pond is high, reducing stress on the larvae.

[0041] When too many crab larvae adhere to the escape-proof net, temporarily close the drain valve 500, gently lower the net into the water and shake it to allow the larvae to detach before continuing. When the escape-proof net is clogged with sludge, temporarily close the drain valve 500 and replace it with a new escape-proof net. When opening the second valve 620 to transfer the crab larvae, the larvae can enter the nursery pond 300 along with the water through the drain pipe 600.

[0042] The beneficial effects of this embodiment are as follows: The water purification tank uses activated sludge 230 and algae 240 to initially purify the water entering from the breeding pond 100, reducing the ammonia nitrogen content. After initial purification in the biological purification tank 210, the water enters the purification tank where biochemical bacteria 250 further purify the water, further reducing the ammonia nitrogen content and ensuring the water quality meets the growth requirements of the crab larvae. The growth plate 211 facilitates the attachment of algae 240 during its growth in the biological purification tank 210, providing more growth space and increasing the quantity of algae 240, thus improving the purification effect of the water in the biological purification tank 210. After the water pump 270 is installed, it can transfer water from the biological water purification tank 210 to the biological water purification tank 220. The biological water purification tank 220 has water entering from the bottom and exiting from the top, which prolongs the water retention time within the tank, improving the water purification effect of the biological bacteria 250. The baffle 221 prevents water from directly impacting the biological bacteria 250 and also prevents bacterial colonies from clogging the tank inlet 531. The screen prevents algae 240 and sludge in the biological water purification tank 210 from clogging the water pump 270 inlet 531. The air pump 400 pumps air into the biological water purification tank 210 and the biological water purification tank 220, allowing the algae 240 and biological bacteria 250 to undergo nitrification in an aerobic environment. Simultaneously, the gas pumped in by the air pump 400 can also strip ammonia nitrogen from the water, and the escaping gas can carry away ammonia nitrogen from the water, further reducing the ammonia nitrogen content in the water. The third aeration unit 430 can oxygenate the aquaculture pond 100. The bottom of the aquaculture pond 100 is conical, which facilitates the discharge of water from the aquaculture pond 100 through the drain outlet.

[0043] Example 3 This embodiment is a third embodiment of a recirculating water seedling system. Based on embodiment two, this embodiment further includes an egg-bearing sand tray 700 for further definition.

[0044] Specifically, the breeding pond 100 is also equipped with a berried sand tray 700 for mud crab seedlings to carry their eggs. The berried sand tray 700 is movably installed within the breeding pond 100. The berried sand tray 700 includes a sand tray frame 710, which is filled with fine sand for the mud crab seedlings to carry their eggs. A support frame 720 is located at the bottom of one end of the sand tray frame 710. The support frame 720 is A-shaped, and its length can be adjusted to change the height of the sand tray frame 710. The support frame 720 can also rotate on the sand tray frame 710, allowing it to be used with different pond bottom structures. A hanging rope is located at the top of the end of the sand tray frame 710 opposite to the support frame. The hanging rope can be secured via hooks on the side wall or top of the breeding pond 100.

[0045] Specifically, the drain valve 500 includes a sleeve 510 installed on the drain outlet. An outer tube 530 is detachably connected to the outer ring of the sleeve 510, and an inner tube 520 is detachably connected to the inner ring of the sleeve 510. An inlet 531 is located at the bottom of the outer tube 530, and an overflow outlet 521 is located on the side wall of the inner tube 520. The sleeve 510 has a convex cross-section, including an outer platform with a larger diameter and an inner platform with a smaller diameter. The inner platform is located above the outer platform, and a through hole for connecting to the drain outlet is located at the center of the inner platform. The bottom of the inner wall of the outer tube 530 is threaded to the outer wall of the outer platform; the bottom of the inner wall of the inner tube 520 is also threaded to the outer wall of the inner platform. The inlet 531 allows water and sludge to pass through while preventing crabs from passing through. There are multiple inlets 531, arranged equidistantly in a circle around the axis of the outer tube 530. There are multiple overflow outlets 521, which are arranged equidistantly in a circle around the axis of the inner pipe 520. The length of the inner pipe 520 is not less than the length of the outer pipe 530.

[0046] The working principle or process of this embodiment is as follows: When the inner pipe 520 is separated from the sleeve 510, the water in the breeding pond 100 can enter the drain pipe 600 through the inlet 531 on the outer pipe 530 to drain sewage and change water in the breeding pond 100; when both the inner pipe 520 and the outer pipe 530 are separated from the sleeve 510, the entire breeding pond 100 can be quickly changed and cleaned.

[0047] The beneficial effects of this embodiment are as follows: The inclusion of a brooding sand tray 700 within the rearing pond 100 allows it to be used for brooding crab larvae when not being used for raising zoea larvae, thus improving the utilization rate of the pond 100. When the rearing pond 100 is used for brooding crabs, the drainage valve 500, with its inner pipe 520 and outer pipe 530, eliminates the need for an escape-prevention net at the drainage outlet.

[0048] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0049] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A recirculating water seedling cultivation system, characterized in that, It includes a breeding pond (100), a biochemical water purification module (200), and a pre-breeding pond (300), wherein the breeding pond (100) is connected to the biochemical water purification module (200) and the pre-breeding pond (300); The breeding pond (100) can be used to raise zoea larvae; The biochemical water purification module (200) can remove ammonia and nitrogen from the water in the breeding pond (100) through nitrification by bacteria and algae before re-introducing the purified water into the breeding pond (100); the standard breeding pond (300) can provide hiding places for crab seedlings.

2. The recirculating water seedling system according to claim 1, characterized in that, The biochemical water purification module (200) includes a biochemical water purification tank (210) and a biochemical water purification container (220); The biochemical water purification tank (210) is connected to the aquaculture tank (100). The bottom of the biochemical water purification tank (210) is covered with activated sludge (230), and the biochemical water purification tank (210) contains algae (240) that can perform nitrification. The bottom of the biochemical water purification tank (220) is connected to the biochemical water purification pool (210), and the top of the biochemical water purification tank (220) is connected to the water inlet of the breeding pool (100). The biochemical water purification tank (220) is equipped with biochemical bacteria (250). Water in the biochemical water purification tank (210) can flow into the aquaculture pond (100) along the biochemical water purification box (220).

3. The recirculating water seedling system according to claim 2, characterized in that, A partition (221) is fixedly installed inside the biochemical water purification tank (220). The partition (221) divides the biochemical water purification tank (220) into a top cavity and a bottom cavity. A plurality of water-permeable holes are arrayed on the partition (221). The top of the top cavity is connected to the water inlet of the aquaculture tank (100), and the biochemical bacteria (250) are located inside the top cavity; The bottom cavity and the biochemical water purification tank (210) are connected by an inlet pipe (260), and a water pump (270) is connected to one end of the inlet pipe (260) located inside the biochemical water purification tank (210).

4. The recirculating water seedling system according to claim 3, characterized in that, The biochemical water purification tank (210) is provided with a growth plate (211) for algae (240) to attach to. The growth plate (211) is fixedly installed at one end of the biochemical water purification tank (210) away from the bottom surface of the biochemical water purification tank (210).

5. A recirculating water seedling system according to claim 4, characterized in that, It also includes an air pump (400), a first aeration section (410) and a second aeration section (420). The air outlet of the air pump (400) is connected to the first aeration section (410) through a first air pipe (411). The air pump (400) is connected to the second aeration section (420) through a second air pipe (421). The first aeration section (410) is fixedly installed in the bottom cavity. The second aeration section (420) is located in the biochemical water purification tank (210) and the second aeration section (420) is closer to the bottom surface of the biochemical water purification tank (210) than the growth plate (211).

6. The recirculating water seedling system according to claim 5, characterized in that, It also includes a third aeration unit (430), which is connected to the air outlet of the air pump (400) via a third air pipe (431), and the third aeration unit (430) is fixedly installed on the bottom surface of the aquaculture pond (100).

7. A recirculating water seedling system according to claim 3, characterized in that, The water pump (270) has a baffle net at its inlet (531), and the baffle net is detachably connected to the water pump inlet (531).

8. A recirculating aquaculture system for seedling raising according to any one of claims 2-7, characterized in that, The bottom of the breeding pond (100) is conical, and a drain outlet is provided at the conical tip of the bottom of the breeding pond (100). The drain outlet is equipped with a drain valve (500) and a drain pipe (600). The drain valve (500) is located at the water inlet end of the drain pipe (600). The drain pipe (600) is also equipped with a first valve (610), a second valve (620) and a third valve (630). The first valve (610) is connected to the water inlet end of the biochemical water purification pond (210); the second valve (620) is connected to the water inlet end of the standard breeding pond (300); and the third valve (630) can be connected to the water inlet end of the sewage discharge pond.

9. A recirculating water seedling system according to claim 8, characterized in that, The breeding pond (100) is also equipped with an egg-bearing sand tray (700) for crab seedlings to carry their eggs. The egg-bearing sand tray (700) is movably installed in the breeding pond (100).

10. A recirculating water seedling system according to claim 9, characterized in that, The drain valve (500) includes a sleeve (510) installed on the drain outlet. The outer ring of the sleeve (510) is detachably connected to an outer tube (530), and the inner ring of the sleeve (510) is detachably connected to an inner tube (520). The bottom of the outer tube (530) is provided with a water inlet (531), and the side wall of the inner tube (520) is provided with an overflow outlet (521).

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