A seawater treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles

Abstract

This invention discloses a seawater treatment system for aquatic organism seedling and larval cultivation based on a natural ecological cycle. The system includes a natural sedimentation tank, a secondary sedimentation algae cultivation tank, a multi-stage dark sedimentation tank, a primary sand filter, a secondary sand filter, and a water storage tank connected to the end of the secondary sand filter. A pump is installed to connect to a water storage tower. A seawater concentration device and an ultrafiltration device are also included between the water storage tower and the aquatic organism seedling tank. The secondary sedimentation algae cultivation tank can be directly connected to a juvenile shellfish rearing tank for direct use in juvenile shellfish cultivation. The sand filter also features a backwashing design for easy recycling. The seawater processed through the primary and secondary sand filters, concentration device, and ultrafiltration device can be used for larval cultivation of aquatic organisms. This water treatment system, through its multi-stage structural design and combined with natural environmental control of light and shading, avoids the drawbacks of chemical and biological purification and the shortcomings of simple physical sand filtration in a natural and ecological way. This ensures a large-scale supply of water for aquatic organism seedling and shellfish cultivation, meeting the diverse needs of large industrial areas.

Description

Technical Field

[0001] This invention relates to the field of seawater treatment technology for aquatic organism seedling cultivation and seedling raising, specifically to a seawater treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles. Background Technology

[0002] With the improvement of people's living standards, consumers' recognition and demand for seafood are increasing, leading to the continuous development of the mariculture industry. Mariculture is a method of artificially cultivating seafood in tidal flats, shallow seas, and other areas, constituting an important part of my country's aquaculture industry. Before aquaculture, the seawater used must be purified to ensure it meets standards and reduces the harm of pollutants to farmed aquatic products.

[0003] Furthermore, data from the "2023 East China Sea Marine Ecological Early Warning and Monitoring Bulletin" released by the State Oceanic Administration shows that the marine environmental pollution situation in the East China Sea remains severe. A total of 24 red tides were detected in the East China Sea, with a cumulative area of ​​1,016 square kilometers for the year. Among them, 17 were harmful red tides, with a cumulative area of ​​869 square kilometers. In addition, the nearshore seawater in the East China Sea generally contains a large amount of silt and impurities. The current pretreatment methods for aquaculture source water, such as ordinary physical sand filtration, cannot remove organic matter and some impurities in the water, affecting subsequent aquaculture or seedling cultivation. Introducing chemical treatment methods may cause secondary pollution and also lead to a significant increase in costs. Biological methods are highly dependent on site maintenance and equipment. Therefore, conventional and simple biological treatment is not very necessary. Summary of the Invention

[0004] In view of the prior art, the purpose of this invention is to provide a water treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles. The system uses physical methods to perform multi-stage sedimentation, dark sedimentation and multi-stage sand filtration on seawater in natural sea areas, thereby fully pre-treating the source water. Furthermore, the pre-treatment system of this invention has a simple structure, long maintenance cycle and can be adapted to the construction of large or small sites.

[0005] To achieve the above objectives, the technical solution adopted by this invention is as follows: a seawater treatment system for aquatic organism seedling cultivation and seedling raising based on a natural ecological cycle, comprising a natural sedimentation tank, which is equipped with a water inlet pipe connected to a natural sea area. The water inlet pipe is used to draw seawater from the natural sea area into the large natural sedimentation tank, which covers an area of ​​60-100 mu (approximately 4 hectares) and is used for the initial sedimentation of suspended sediment and impurities in the seawater of the natural sea area; a secondary sedimentation algae cultivation tank, covering an area of ​​15-20 mu (approximately 1 hectares) and equipped with a steep gate between it and the natural sedimentation tank, which draws the relatively clear upper layer of seawater from the natural sedimentation tank after the first sedimentation into the secondary sedimentation algae cultivation tank. The secondary sedimentation algae cultivation tank is connected to a multi-stage dark sedimentation tank. Both the natural sedimentation tank and the secondary sedimentation algae cultivation tank are set up in a natural environment. Seawater passing through the natural sedimentation tank and then into the secondary sedimentation algae cultivation tank undergoes sedimentation and continuous sunlight exposure, resulting in the formation of abundant natural marine unicellular algae. The multi-stage dark sedimentation tank consists of a large 5000 cubic meter tank divided into several sub-tanks. A first shade net is installed above the multi-stage dark sedimentation tank. The partition walls between the sub-tanks include overflow walls with overflow pipes at the top and bottom seepage walls with inlets at the bottom. The sub-tanks are also lined with seepage boards and a pebble sedimentation layer. The multi-stage dark sedimentation tank is used for multi-stage filtration and sedimentation of algal carcasses that have died due to lack of sunlight. The sand filter is equipped with a water pump to draw seawater from the sub-sedimentary tank at the end of a multi-stage dark sedimentation tank. The primary sand filter includes an overflow sedimentation tank, a multi-layer filter, and a bottom infiltration tank. The main pipeline connected to the water pump is equipped with a tee connecting a first branch pipe and a second branch pipe. The first branch pipe connects to the bottom infiltration tank, which supplies water to the overflow sedimentation tank. The overflow sedimentation tank supplies water to the multi-layer filter, and an overflow pipe connects the overflow sedimentation tank and the multi-layer filter. The second branch pipe connects to the multi-layer filter. Valves are installed on both the first and second branch pipes to control the flow of water. The multi-layer filter is connected to the overflow sedimentation tank via an overflow pipe. It has an outlet chamber at its bottom with an outlet pipe, and an opening at the top of the outlet chamber. The filter consists of a perforated plate with multiple layers of filter media, including a fine sand layer, a gravel layer, and a pebble layer arranged from top to bottom. A drain pipe is installed at a depth of 1 cm above the fine sand layer, connecting to a drainage ditch outside the multi-layer filter. The outlet of the second branch pipe connects to an outlet chamber, which is also connected to a high-pressure air pump. A secondary sand filter is constructed identically to the primary sand filter, except that it has a second shade net at its top. The end of the secondary sand filter is connected to a water storage tank, and a pump is installed to connect to a water tower. A seawater regulation device, including an ultrafiltration device or an osmotic pressure device, is also included between the water tower and the aquaculture and seedling pond to control and regulate the salinity of the purified seawater.

[0006] As a further step in the above scheme, after the seawater from the natural sea area is introduced into the natural sedimentation tank, it is left to stand for 15 days during one tide. The steep gate is then opened to allow the seawater, which has undergone preliminary sedimentation in the natural sedimentation tank, to be placed into the secondary sedimentation algae cultivation tank. After the seawater has been left to stand in the secondary sedimentation algae cultivation tank for 7 days, the water pump can be turned on to pump the seawater through the water pumping pipe into the multi-stage dark sedimentation tank for further treatment, or it can be introduced into the intermediate cultivation tank for juvenile shellfish in the tidal flats. The algae that have multiplied in large quantities in the secondary sedimentation algae cultivation tank can be used as food for the juvenile shellfish.

[0007] As a further feature of the above scheme, the steep gate is located between the natural sedimentation tank and the secondary sedimentation algae cultivation tank. The steep gate opens the waterway from top to bottom, allowing seawater to flow from the upper layer of the natural sedimentation tank to the secondary sedimentation algae cultivation tank. The natural sedimentation tank and the secondary sedimentation algae cultivation tank are used to carry out two long-term sedimentation processes for the silt in the seawater. Based on sunlight, after a certain period of sedimentation, the native algae in the relatively clear seawater multiply in large quantities, reducing the large amount of organic matter in the seawater in the natural sea area.

[0008] As a further feature of the above scheme, the multi-stage dark sedimentation tank is designed with overflow walls and bottom seepage walls. The dark sedimentation sub-tank is further divided into an overflow sub-tank and a bottom seepage sub-tank. Both the overflow sub-tank and the bottom seepage sub-tank are equipped with seepage plates and a pebble sedimentation layer on the seepage plates. The bottom of the seepage plates is also provided with cavities. The seawater in the overflow sub-tank and the bottom seepage sub-tank undergoes a Z-shaped flow relative to the overflow sub-tank and the bottom seepage sub-tank. The first shading net is used to reduce or eliminate sunlight to promote the death and sedimentation of a large number of algae.

[0009] As a further feature of the above scheme, the second branch pipe and high-pressure air pump installed in the primary sand filter tank are used to activate the backwashing function after the outlet pipe is closed. Water is flushed in the outlet chamber through the second branch pipe. The backwash water flows back up to the multi-layer filter media after passing through the perforated plate. The high-pressure air pump, together with the water and air mixture, rises up and breaks up the agglomeration of the multi-layer filter media, thus thoroughly cleaning it.

[0010] As a further provision of the above scheme, the sewage pipe includes a drain pipe fixed on the wall of the multi-layer filter tank and a pipe plug. The pipe plug includes a hollow pipe that matches the drain pipe with an upward opening. After the hollow pipe is inserted into the drain pipe, it forms a sealed sewage pipe.

[0011] As a further feature of the above scheme, the high-pressure air pump is equipped with an air guide pipe, the opening of which is located on the lower side of the perforated plate, and multiple rows of air jet pipes are arranged on the side of the air guide pipe that is far away from the sewage pipe of the multi-layer filter tank wall. The air jet pipes are controlled by an air valve located outside the multi-layer filter tank to release air.

[0012] As a further feature of the above scheme, the fine sand layer has a fine sand particle size of 1-2 mm, the gravel layer has a gravel particle size of 3-5 mm, the pebble layer has a pebble particle size of 5-6 cm, the fine sand layer has a thickness of 50 cm, the gravel layer has a thickness of 40 cm, and the pebble layer has a thickness of 30 cm.

[0013] Beneficial effects: The seawater seedling cultivation and aquaculture water treatment system based on natural ecology provided by this invention has the following characteristics:

[0014] 1. The East China Sea is relatively turbid, and the seawater in the natural sea area carries a large amount of silt and impurities. The sedimentation process is combined with sunlight, which allows the algae in the water to reproduce in large quantities through photosynthesis and absorb organic nutrients from the water. The seawater rich in natural algae can also be supplied to aquaculture ponds, saving costs.

[0015] 2. After initial separation of impurities from seawater using sedimentation, the seawater is introduced into a dark sedimentation tank without light, causing a large number of algae to die. Combined with bottom infiltration and a pebble array, this reduces water flow velocity and accelerates the sedimentation of dead algae and impurities. The dead algae also act as natural nuclei and attachment sites for organisms; fine particles adhere to the surface of the algae or its remaining structure. Since algae have a certain volume and weight, the overall weight increases when suspended particles attach, thus accelerating the sedimentation process.

[0016] 3. The dark sedimentation tank features a Z-shaped baffle design. The combination of overflow and bottom infiltration, along with layers of pebbles to enhance filtration, further reduces the flow velocity of the seawater. The overflow draws relatively clear seawater from the upper layer into the next sub-tank, improving the purification effect.

[0017] 4. The sand filter draws water from the sedimentation tank and has an overflow system before it. This system can further settle the water and reduce the water flow rate in the filter, making it closer to natural water infiltration. The filtered and settled impurities are not easily disturbed by the water flow. The sand filter is equipped with a simple and convenient backwashing device and a high-pressure air pump that uses air-water mixing for backwashing through air pipes. The distributed air pipes allow the air-carrying water to be distributed and fully agitate and wash the filter media. Furthermore, by controlling the air jets from the air pipes, the turbid wastewater can be more easily discharged towards the sewage outlet.

[0018] 5. The sand filter is equipped with two stages: one with light and one without light. After secondary propagation, the organic matter in the water is further reduced. The water in the dark sand filter is then left to stand in a water tower and then passed through an ultrafiltration membrane or osmotic pressure technology. It can be used directly for seedling cultivation or aquaculture. The ultrafiltration membrane only allows solvents (such as water molecules), inorganic salts and small organic molecules in the solution to pass through, while retaining large molecules such as suspended solids, colloids, proteins and microorganisms in the solution, thereby achieving the purpose of purification or separation. The seawater conditioning device is adjusted according to the seawater osmotic pressure to control and regulate the salinity of the purified seawater to meet the needs of seedling cultivation.

[0019] The marine organism seedling and cultivation water treatment system of the present invention has a simple structure and easy setup. The size and structure of the device can be adaptively adjusted according to the site conditions. Through multi-level structural design, combined with natural environmental regulation of light and shading, it avoids the drawbacks of chemical and biological purification and the shortcomings of simple physical sand filtration in a natural and ecological way, thereby ensuring the supply of a large amount of aquaculture water to meet the needs of large-scale aquaculture. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structural composition of the water treatment system of the present invention.

[0021] Figure 2 This is a schematic diagram of the sand filter structure of the present invention.

[0022] Figure 3 This is a schematic cross-sectional view of the sand filter of the present invention.

[0023] Figure 4 This is a schematic diagram of the structure of the sand filter overflow sedimentation tank and the bottom infiltration tank of the present invention.

[0024] Figure 5 This is a schematic diagram of the multi-layer filter structure of the present invention.

[0025] Attached reference numerals: 1. Natural sedimentation tank; 10. Natural sea area; 11. Water intake pipe; 12. Slack gate; 2. Secondary sedimentation and algae cultivation tank; 3. Multi-stage dark sedimentation tank; 31. Dark sedimentation sub-tank; 311. Overflow sub-tank; 312. Bottom seepage sub-tank; 33. Partition wall; 34. Overflow pipe; 35. Overflow wall; 36. Water outlet; 37. Bottom seepage wall; 38. Seepage plate; 39. Pebble sedimentation layer; 4. Primary sand filter; 41. Water pump; 411. Main pipe; 413. First branch pipe; 414 42. Second branch pipe; 43. Overflow sedimentation tank; 44. Multi-layer filter; 45. Outlet pipe; 46. Outlet chamber; 47. Perforated infiltration plate; 48. Multi-layer filter media; 49. Fine sand layer; 40. Gravel layer; 41. Pebble layer; 42. Sewage pipe; 43. High-pressure air pump; 44. Bottom infiltration tank; 45. Valve; 66. Secondary sand filter; 77. Pump; 88. Water storage tower; 99. Aquaculture and seedling rearing pond; 100. Seawater regulating device; 11. Intermediate rearing pond for juvenile shellfish in tidal flats. Detailed Implementation

[0026] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments and features described in these embodiments can be combined with each other.

[0027] like Figure 1-5The present invention discloses a seawater treatment system for aquatic organism seedling cultivation and seedling raising based on a natural ecological cycle. It includes a natural sedimentation tank 1, which is connected to a natural sea area 10 via a water inlet pipe 11 or a sluice gate 12. The water inlet pipe 11 or sluice gate 12 draws seawater from the natural sea area 10 into the large natural sedimentation tank 1. The natural sedimentation tank 1 covers an area of ​​60-100 mu (approximately 4 hectares) and is used for the initial sedimentation of suspended sediment and impurities in the seawater of the natural sea area 10. A secondary sedimentation algae cultivation tank 2, covering an area of ​​15-20 mu (approximately 1 hectares), is connected to the natural sedimentation tank 1 via a sluice gate 12. The sluice gate 12 draws relatively clear upper layer seawater from the natural sedimentation tank 1, after the first sedimentation, into the secondary sedimentation algae cultivation tank 2. The secondary sedimentation algae cultivation tank 2 is connected to... The system connects to a multi-stage dark sedimentation tank 3. Both the natural sedimentation tank 1 and the secondary sedimentation algae cultivation tank 2 are located in a natural environment. After sedimentation and continuous sunlight exposure, the seawater passing through the natural sedimentation tank 1 and the secondary sedimentation algae cultivation tank 2 will form abundant natural marine unicellular algae. The multi-stage dark sedimentation tank 3 is a large 5000 cubic meter tank divided into several dark sedimentation sub-tanks 31. A first shade net is installed above the multi-stage dark sedimentation tank 3. The partition walls 33 between the dark sedimentation sub-tanks 31 include overflow walls 35 with overflow pipes 34 at the top and bottom seepage walls 37 with water outlets 36 at the bottom. The dark sedimentation sub-tanks 31 are also lined with seepage boards 38 and a pebble sedimentation layer 39. 3. Used for multi-stage filtration and sedimentation of algal carcasses that have died due to lack of sunlight in seawater; 4. Primary sand filter, equipped with a water pump 41, draws seawater from the dark sedimentation sub-pool 31 after sedimentation at the end of the multi-stage dark sedimentation tank 3. The primary sand filter 4 includes an overflow sedimentation tank 42, a multi-layer filter 43, and a bottom infiltration tank 44. The main pipe 411 connected to the water pump 41 is equipped with a tee connecting a first branch pipe 413 and a second branch pipe 414. The first branch pipe 413 is connected to the bottom infiltration tank 44, which supplies water to the overflow sedimentation tank 42. The overflow sedimentation tank 42 supplies water to the multi-layer filter 43, and an overflow pipe 34 is installed between the overflow sedimentation tank 42 and the multi-layer filter 43. The second branch pipe 414 is connected to the multi-layer filter 43. Both the first branch pipe 413 and the second branch pipe 414 are equipped with valves 45 to control the flow of water; the multi-layer filter tank 43 is connected to the overflow sedimentation tank 42 for water intake through the overflow pipe 34, and the bottom of the filter tank 433 is equipped with an outlet chamber 432 with an outlet pipe 431. The top of the outlet chamber 432 is equipped with a perforated plate 433, and the perforated plate 433 is equipped with multiple layers of filter media 434, including a fine sand layer 4341, a gravel layer 4342, and a pebble layer 4343 arranged from top to bottom. A sewage pipe 435 is installed 2-3 cm above the fine sand layer 4341. The sewage pipe 435 is connected to the drainage ditch outside the multi-layer filter tank 43. The outlet of the second branch pipe 414 is connected to the outlet chamber 432. The outlet chamber 432 is also connected to a high-pressure air pump 436.The secondary sand filter 5 is identical to the primary sand filter 4, except that it has a second shade net at its top. The end of the secondary sand filter 5 is connected to a water storage tank, and a pump 61 is connected to a water storage tower 62. A seawater regulating device 7 is also included between the water storage tower 62 and the aquaculture and seedling pond 63. The seawater regulating device 7 includes an ultrafiltration device or an osmotic pressure device, used to control and regulate the salinity and other properties of the purified seawater.

[0028] As a further step in the above scheme, after the seawater in the natural sea area 10 is introduced into the natural sedimentation tank 1, it is left to stand for 15 days during one tide. The steep gate 12 is then opened to put the seawater that has undergone preliminary sedimentation in the natural sedimentation tank 1 into the secondary sedimentation algae cultivation tank 2. After the seawater has been left to stand in the secondary sedimentation algae cultivation tank 2 for 7 days, the water pump can be turned on to pump the seawater through the water pumping pipe into the multi-stage dark sedimentation tank 3 for further treatment, or it can be introduced into the intermediary cultivation tank 9 for juvenile shellfish in the tidal flats. The algae that have multiplied in large quantities in the secondary sedimentation algae cultivation tank 2 can be used as food for the juvenile shellfish.

[0029] As a further feature of the above scheme, the steep gate 12 is located between the natural sedimentation tank 1 and the secondary sedimentation algae cultivation tank 2. The steep gate 12 opens the waterway from top to bottom to allow seawater to flow from the upper layer of the natural sedimentation tank 1 to the secondary sedimentation algae cultivation tank 2. The natural sedimentation tank 1 and the secondary sedimentation algae cultivation tank 2 are used to carry out two long-term sedimentation processes for the silt in the seawater. Based on sunlight, after a certain period of sedimentation, the native algae in the relatively clear seawater will multiply in large quantities, reducing the large amount of organic matter in the seawater in the natural sea area.

[0030] As a further feature of the above scheme, the multi-stage dark sedimentation tank 3 is further divided into an overflow sub-tank 31 and a bottom seepage sub-tank 312 based on the overflow wall 35 and the bottom seepage wall 37. Both the overflow sub-tank 311 and the bottom seepage sub-tank 312 are provided with a seepage plate 38 and a pebble sedimentation layer 39 located on the seepage plate 38. The bottom of the seepage plate 38 is also provided with a cavity 381. The seawater in the overflow sub-tank 311 and the bottom seepage sub-tank 312 undergoes a Z-shaped deflection relative to the overflow sub-tank 311 and the bottom seepage sub-tank 312. The first shading net is used to reduce or eliminate sunlight to promote the death and sedimentation of a large number of algae.

[0031] As a further feature of the above scheme, the second branch pipe 414 and the high-pressure air pump 436 installed in the primary sand filter tank 4 are used to activate the backwashing function after the outlet pipe 431 is closed. Water is flushed in the outlet chamber 432 through the second branch pipe 414. The backwash water flows backward through the perforated plate 433 and surges upward to the multi-layer filter media 434. The high-pressure air pump 436 forms a water-air mixture that surges upward, while breaking up the clumps of the multi-layer filter media 434 and thoroughly cleaning it.

[0032] As a further provision of the above scheme, the sewage pipe 435 includes a drain pipe fixed on the wall of the multi-layer filter tank 43 and a pipe plug 4351. The pipe plug 4351 includes a hollow pipe that matches the drain pipe with an upward opening. After the hollow pipe is inserted into the drain pipe, it forms a blockage of the sewage pipe 435.

[0033] As a further provision of the above scheme, the high-pressure air pump 436 is provided with an air guide pipe. The opening of the air guide pipe is located on the lower side of the perforated plate 433. The air guide pipe is provided with multiple rows of air jet pipes on the side of the drain pipe 435 that is far away from the wall of the multi-layer filter 43. The air jet pipes are controlled to spray air by an air valve located outside the multi-layer filter 43.

[0034] As a further feature of the above scheme, the fine sand layer 4341 has a fine sand particle size of 1-2 mm, the gravel layer 4342 has a gravel particle size of 3-5 mm, the pebble layer 4343 has a pebble particle size of 5-6 cm, the fine sand layer 4341 has a thickness of 50 cm, the gravel layer 4342 has a thickness of 40 cm, and the pebble layer 4343 has a thickness of 30 cm.

[0035] The seawater seedling and aquaculture water treatment system based on natural ecological cycle of the present invention requires a stage of seawater sedimentation and purification process during use. The entire process generally takes 20-30 days. Among them, the seawater in the natural sea area 10 needs to undergo nearly 15 days of sedimentation after being introduced into the natural sedimentation tank 1. It is worth noting that one meaning of this setting is that a steep gate 12 may be set on the water inlet side of the natural sedimentation tank 1 and the natural sea area 10. When the water level in the natural sedimentation tank 1 is low, the steep gate 12 is opened to allow seawater to backflow into the natural sedimentation tank 1 during the highest tide. Then, after the tide recedes, the steep gate 12 is closed to complete the first stage of water storage. In the natural sedimentation tank 1, the seawater undergoes static sedimentation, and the suspended silt and impurities in it will slowly settle. At the same time, the exposure to sunlight also causes some single-celled algae in the natural aquatic ecosystem to begin to reproduce.

[0036] After entering the secondary sedimentation algae cultivation tank 2, the seawater is left to stand for another 7 days. The transition from the natural sedimentation tank 1 to the secondary sedimentation algae cultivation tank 2 involves diverting relatively clear seawater from the upper layer. The seawater in the secondary sedimentation algae cultivation tank 2 is even clearer, without a large amount of silt and impurities. Sunlight can penetrate the seawater, which is conducive to the photosynthetic growth of algae. The natural unicellular algae in the seawater will multiply in large quantities, gradually filling the seawater with a large amount of algae. During this process, an aeration device can be added to introduce air to increase the dissolved oxygen in the seawater and help the algae photosynthesis. After 7 days of secondary sedimentation and algae reproduction, not only is seedling water with a large amount of unicellular algae obtained, which can be used as food for juvenile shellfish (if needed, it can be introduced into the intermediate juvenile shellfish cultivation tank 9 in the tidal flats for seedling cultivation), but the reproduction of algae can also consume nutrients in the water.

[0037] After seawater containing a large amount of algae is pumped into the multi-stage dark sedimentation tank 3, a first shade net is installed above the tank. Deprived of sunlight, the algae can no longer photosynthesize, resulting in a large-scale death of the algae. The dead algae suspend in the seawater, forming a large amount of flocculent matter. These dead algae also act as adsorption nuclei, further adsorbing fine impurities in the seawater. Furthermore, after entering the multi-stage dark sedimentation tank 3, the seawater undergoes intermittent filtration through the overflow sub-tank 311 and the bottom seepage sub-tank 312, further enhancing the purification effect. Specifically, after entering the multi-stage dark sedimentation tank 3, the seawater passes through the overflow sub-tank 311... The water flows through the bottom permeation plate 38 and then through the pebble sedimentation layer 39. It then flows into the bottom permeation sub-pool 312 through the overflow pipe 34 on the overflow wall 35 near the top. After passing through the pebble sedimentation layer 39 and the permeation plate 38 in the bottom permeation sub-pool 312, it enters the bottom of the next overflow sub-pool 311 through the bottom water outlet 36 from the bottom permeation wall 37. It then flows through the pebble sedimentation layer 39 again through the bottom permeation plate 38. This process is repeated multiple times. The water flow adopts natural flow and overflow methods. Pumps are installed in the front and rear pools. The water flows by itself due to the height difference of the water level, which reduces turbulence and improves the sedimentation effect.

[0038] Furthermore, the seawater purified by the multi-stage dark sedimentation tank 3 is pumped into the sand filter. The sand filter is set up as a primary sand filter 4 and a secondary sand filter 5. The difference between the two is that the primary sand filter 4 is under natural sunlight, while the secondary sand filter 5 is equipped with a second shade net to block the light. The purpose is still to kill algae that may grow during the sand filtration process by shading them before filtering them.

[0039] It is worth noting that the primary sand filter 4 in this embodiment is divided into three sub-pools. According to the direction of water flow, the sub-pools are connected to the bottom infiltration tank 44, the overflow sedimentation tank 42, and the multi-layer filter 43, which is the main function. The main pipe 411 that draws water from the multi-stage dark sedimentation tank 3 is branched into a first branch pipe 413 and a second branch pipe 414 after passing through a valve 45. The first branch pipe 413 is connected to the upper end of the bottom infiltration tank 44. The bottom of the bottom infiltration tank 44 is provided with a water outlet connected to the overflow sedimentation tank 42. Seawater flows in from the upper end of the bottom infiltration tank 44 and flows through a U-shaped flow. It overflows from the overflow pipe 34 in the upper part of the overflow sedimentation tank 42 into the multi-layer filter 43. After passing through the multi-layer filter media 434 from top to bottom, it flows into the outlet chamber 432 from the perforated infiltration plate 433 and then connects to the outlet pipe 431 for water discharge.

[0040] The second branch pipe 414 is directly connected to the outlet chamber 432. The purpose of setting the second branch pipe 414 is to realize the backwashing of the multi-layer filter 43. The backwashing setting structure of this embodiment is simple and easy to operate. The steps include: ① The operator first removes the plug 4351 on the sewage pipe 435, then closes the outlet pipe 431, and then closes the first branch pipe 413; ② Then open the valve 45 of the previously closed second branch pipe 414. At this time, the extracted seawater no longer enters the bottom infiltration tank 44 from the first branch pipe 413, but enters the outlet chamber 432 from the second branch pipe 414. The outlet chamber 432 is located below the perforated infiltration plate 433. The bottom inlet and outlet pipe 431 cannot discharge water, and the high-pressure water will surge upward, lifting the hardened multi-layer filter material 434.

[0041] ③ Furthermore, in order to better perform backwashing, the sand filter in this embodiment is also equipped with a high-pressure air pump 436, and the air pipe is connected to the outlet chamber 432. During backwashing, the high-pressure air pump 436 is turned on simultaneously to force high-pressure air into the outlet chamber 432, which mixes with the backwashed seawater to form a water-air mixture. The airflow causes the seawater to form turbulence, and the high-pressure air makes it easier to break up the caking of the multi-layer filter media 434. This allows the impurities and sludge trapped by the multi-layer filter media 434 during forward filtration to be pushed upward and washed away with the rising seawater through the drain pipe 435 to the drainage ditch, thus cleaning the multi-layer filter media 434 and enabling it to be recycled.

[0042] The above operations can be carried out in both the primary sand filter 4 and the secondary sand filter 5, enabling convenient cleaning of the filter media and facilitating periodic recycling. The seawater from the secondary sand filter 5 is then pumped to the water storage tower 62. At this point, impurities and inorganic nutrients in the seawater have been purified. According to the needs, the staff then uses the seawater adjustment device 7 to adjust the salinity and add nutrients through concentration and ultrafiltration, transforming it into biological seedling seawater suitable for aquaculture.

[0043] Compared with existing technologies, the treatment system of this invention is characterized by: firstly, utilizing a natural ecological approach, with virtually no additional chemical or biological intervention in the entire purification process; secondly, relatively low power consumption for the water pumps, which can be supplied by solar power; and thirdly, relatively low cost for the purification system after site maintenance, aligning with sustainable environmental and ecological development. Furthermore, based on the growth of natural single-celled algae, it absorbs nutrients from natural seawater, not only reducing overnutrient levels but also providing food for juvenile shellfish, thus developing a new application in the seawater purification process to meet the needs of cultivation ponds. Additionally, the dead algae that settle into the sediment form adsorption nuclei, further purifying the water. The sludge formed from the filtered algae carcasses can be further processed into ultrafiltration briquettes, which can then be used as fertilizer raw materials for agricultural planting. Furthermore, the multi-stage dark sedimentation tank structure of this invention, through Z-shaped baffles, allows seawater to pass through layers of filtration overflow and bottom infiltration, reducing flow velocity and improving sedimentation efficiency. The branched pipe design of the sand filter simplifies the backwashing filter design and facilitates the application of the entire system. In summary, the water treatment system of this invention, through its multi-stage structural design and the natural environmental regulation of light and shading, avoids the drawbacks of chemical and biological purification and the shortcomings of simple physical sand filtration in a natural and ecological way, thereby ensuring the supply of large quantities of aquaculture water and meeting the needs of large-scale aquaculture operations.

[0044] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A seawater treatment system for aquatic organism seedling cultivation and seedling rearing based on natural ecological cycles, characterized in that, include: A natural sedimentation tank (1) is provided with a water inlet pipe (11) connected to a natural sea area (10). The water inlet pipe (11) is used to draw seawater from the natural sea area (10) into the large natural sedimentation tank (1). The natural sedimentation tank (1) is 60-100 mu in size and is used for the initial sedimentation of suspended sediment and impurities in the seawater of the natural sea area (10). A secondary sedimentation algae cultivation tank (2) is provided with 15-20 mu in size and a steep gate (12) is set between it and the natural sedimentation tank (1). The steep gate (12) draws the relatively clear upper layer of seawater that has undergone one sedimentation in the natural sedimentation tank (1) into the secondary sedimentation algae cultivation tank (2). Within the natural sedimentation tank (1) and the secondary sedimentation tank (2), the seawater passing through the natural sedimentation tank (1) and the secondary sedimentation tank (2) is connected to the multi-stage dark sedimentation tank (3). Both the natural sedimentation tank (1) and the secondary sedimentation tank (2) are set in a natural environment. After sedimentation and continuous sunlight exposure, the seawater in the secondary sedimentation tank (2) will form abundant natural single-cell algae in the water. The multi-stage dark sedimentation tank (3) is a large tank with a volume of 5,000 cubic meters, which is divided into several dark sedimentation sub-tanks (31). A first shade net is also set above the multi-stage dark sedimentation tank (3). The partition wall (33) between the dark sedimentation sub-tanks (31) includes spaced partitions on the upper part. An overflow wall (35) with an overflow pipe (34) and a bottom infiltration wall (37) with a water outlet (36) at the bottom are provided. The dark sedimentation sub-pool (31) is also lined with a permeable plate (38) and a pebble sedimentation layer (39). The multi-stage dark sedimentation tank (3) is used to filter and settle the algae corpses in the seawater that have died due to lack of light. The first-stage sand filter (4) is equipped with a water pump (41) to draw seawater from the dark sedimentation sub-pool (31) after sedimentation at the end of the multi-stage dark sedimentation tank (3). The first-stage sand filter (4) includes an overflow sedimentation tank (42), a multi-layer filter tank (43), and a bottom infiltration tank (44). The water pump (41) The main pipe (411) is connected to the first branch pipe (413) and the second branch pipe (414) by a tee. The first branch pipe (413) is connected to the bottom infiltration tank (44). The bottom infiltration tank (44) is used to supply water to the overflow sedimentation tank (42). The overflow sedimentation tank (42) is used to supply water to the multi-layer filter (43). An overflow pipe (34) is set between the overflow sedimentation tank (42) and the multi-layer filter (43). The second branch pipe (414) is connected to the multi-layer filter (43). Valves (45) are set on both the first branch pipe (413) and the second branch pipe (414) to control the flow of water.The multi-layer filter (43) is connected to the overflow sedimentation tank (42) for water intake via an overflow pipe (34). A water outlet chamber (432) with an outlet pipe (431) is provided at the bottom of the filter. A perforated plate (433) is provided at the top of the water outlet chamber (432). Multiple layers of filter media (434) are provided on the perforated plate (433), including a fine sand layer (4341), a gravel layer (4342), and a pebble layer (4343) arranged sequentially from top to bottom. A sewage pipe (435) is provided 2-3 cm above the fine sand layer (4341). The sewage pipe (435) connects to a drainage ditch outside the multi-layer filter (43). The second branch pipe... The outlet of (414) is connected to the outlet chamber (432), which is also connected to a high-pressure air pump (436); the secondary sand filter (5) is the same as the primary sand filter (4), except that it is equipped with a second shade net on its top, and the end of the secondary sand filter (5) is connected to a water storage tank, and a water pump (61) is connected to a water storage tower (62); a seawater regulating device (7) is also included between the water storage tower (62) and the aquaculture and seedling pond (63), which includes an ultrafiltration device or an osmotic pressure device for controlling and regulating the salinity of the purified seawater.

2. The seawater treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles according to claim 1, characterized in that, After the seawater in the natural sea area (10) is introduced into the natural sedimentation tank (1) and left to stand for 15 days, the steep gate (12) is opened to put the seawater that has undergone preliminary sedimentation in the natural sedimentation tank (1) into the secondary sedimentation algae cultivation tank (2). After the seawater has been left to stand in the secondary sedimentation algae cultivation tank (2) for 7 days, the water pump can be turned on to pump the seawater through the water pumping pipe into the multi-stage dark sedimentation tank (3) for further treatment or to introduce it into the intermediate cultivation tank (9) for juvenile shellfish in the tidal flats. The algae that have multiplied in large quantities in the secondary sedimentation algae cultivation tank (2) can be used as food for juvenile shellfish.

3. The seawater treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles according to claim 2, characterized in that, The steep gate (12) is located between the natural sedimentation tank (1) and the secondary sedimentation algae cultivation tank (2). The steep gate (12) opens the waterway from top to bottom to allow seawater to flow from the upper layer of the natural sedimentation tank (1) to the secondary sedimentation algae cultivation tank (2). The natural sedimentation tank (1) and the secondary sedimentation algae cultivation tank (2) are used to carry out two long-term sedimentation of the mud and sand in the seawater. Based on the sunlight, after a certain period of sedimentation, the native algae in the relatively clear seawater will multiply in large quantities, reducing the large amount of organic matter in the seawater in the natural sea area.

4. The seawater treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles according to claim 1, characterized in that, The multi-stage dark sedimentation tank (3) is based on the overflow wall (35) and the bottom seepage wall (37). The dark sedimentation sub-tank (31) is further divided into an overflow sub-tank (311) and a bottom seepage sub-tank (312). Both the overflow sub-tank (311) and the bottom seepage sub-tank (312) are equipped with a seepage plate (38) and a pebble sedimentation layer (39) located on the seepage plate (38). The bottom of the seepage plate (38) is also provided with a cavity (381). The seawater in the overflow sub-tank (311) and the bottom seepage sub-tank (312) undergoes a Z-shaped deflection relative to the overflow sub-tank (311) and the bottom seepage sub-tank (312). The first shade net is used to reduce or eliminate sunlight to cause a large number of algae to die and settle.

5. The seawater treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles according to claim 1, characterized in that, The second branch pipe (414) and high-pressure air pump (436) installed in the primary sand filter (4) are used to start the backwashing function after the outlet pipe (431) is closed. Water is flushed in the outlet chamber (432) through the second branch pipe (414). The backwash water flows back up to the multi-layer filter media (434) after passing through the perforated plate (433). The high-pressure air pump (436) forms a water-air mixture that flows up while breaking up the clumps of the multi-layer filter media (434) and cleaning it thoroughly.

6. The seawater treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles according to claim 5, characterized in that, The sewage pipe (435) includes a drain pipe fixed on the wall of the multi-layer filter (43) and a plug (4351). The plug (4351) includes a hollow pipe that matches the drain pipe which opens upward. The hollow pipe is inserted into the drain pipe to form a plugged sewage pipe (435).

7. A seawater treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles according to claim 6, characterized in that, The high-pressure air pump (436) is equipped with an air guide pipe. The opening of the air guide pipe is located on the lower side of the perforated plate (433). The air guide pipe is equipped with multiple rows of air jet pipes on the side of the drain pipe (435) that is far away from the wall of the multi-layer filter (43). The air jet pipes are controlled by an air valve located outside the multi-layer filter (43) to spray air.

8. A seawater treatment system for aquatic organism seedling cultivation and seedling raising based on natural ecological cycles according to claim 1, characterized in that, The fine sand layer (4341) has a fine sand particle size of 1-2 mm, the gravel layer (4342) has a gravel particle size of 3-5 mm, the pebble layer (4343) has a pebble particle size of 5-6 cm, the fine sand layer (4341) has a thickness of 50 cm, the gravel layer (4342) has a thickness of 40 cm, and the pebble layer (4343) has a thickness of 30 cm.

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