Equipment and method for removing seawater microplastics by utilizing multilayer biodeposition filtering system

Abstract

The invention relates to the technical field of seawater micro-plastic treatment, and particularly discloses equipment and a method for removing seawater micro-plastics by using a multilayer biodeposition filtering system.The equipment comprises a first filtering cylinder, a second filtering cylinder and a third filtering cylinder, the second filtering cylinder is inserted in the middle of the first filtering cylinder, and the third filtering cylinder is inserted in the middle of the second filtering cylinder; the bottom of the first filter cartridge is connected with a micro-plastic collecting box; the micro-plastic collecting box is communicated with the first filter cartridge, the second filter cartridge and the third filter cartridge; through natural filtration and deposition functions of the multi-layer biological deposition system, micro-plastic particles in seawater are efficiently removed. Through reasonable configuration and optimization of combination of different organisms, the capture rate and sedimentation efficiency of the micro-plastics are improved, and water body pollution is remarkably reduced. An innovative, effective and sustainable solution is provided for solving the problem of micro-plastic pollution of the water body, and development of a green and environment-friendly breeding technology and progress of water resource protection are promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of seawater microplastic treatment, and specifically to equipment and a method for removing seawater microplastics by utilizing a multi-layer biological sedimentation filtration system. Background Art

[0002] At present, the methods for dealing with microplastics in seawater mainly focus on the following aspects: Physical filtration: Use fine meshes or sieves to catch microplastic particles in seawater. This method is suitable for larger particles of microplastics, but has limited effect on smaller particles. Chemical degradation: Some chemical reagents and catalysts can accelerate the degradation process of microplastics and break down plastics into harmless small molecules. However, these methods need to be carried out in laboratory environments and have not yet been applied on a large scale. Biodegradation: Certain microorganisms can decompose specific types of plastics. Researchers are exploring how to use these microorganisms to deal with microplastics in the ocean. It should be pointed out that most of the current treatment technologies for marine microplastics are still in the research and development and testing stages, and have not yet been applied on a large scale in actual marine cleaning projects. Efforts are still needed to find more efficient, economical and environmentally friendly methods to solve this problem.

[0003] There are a large number of microplastics in the existing seawater, but the existing treatment methods are relatively simple and cannot grade, filter and collect the microplastics in the seawater, resulting in many smaller microplastics being difficult to collect and existing in the seawater for a long time, affecting the quality of the seawater. In addition, the existing technology does not use marine organisms to aggregate and collect microplastics of different particle sizes in the seawater, resulting in many small microplastics being difficult to collect. In addition, the existing microplastic treatment methods do not combine marine aquaculture with microplastic collection, and cannot collect and aggregate microplastics during the aquaculture process, which cannot increase profits and also increases the cost of microplastic collection. Therefore, an apparatus and method for removing seawater microplastics using a multi-layer biological sedimentation filtration system are provided. Summary of the invention

[0004] The purpose of the present invention is to address the defects of the prior art and provide an apparatus and method for removing microplastics from seawater using a multi-layer biological sedimentation filtration system to solve the problems raised by the above-mentioned background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solution: an apparatus for removing microplastics from seawater using a multi-layer biological sedimentation filtration system, comprising a first filter cartridge, a second filter cartridge, and a third filter cartridge, wherein the second filter cartridge is inserted in the middle of the first filter cartridge, the third filter cartridge is inserted in the middle of the second filter cartridge, and a microplastic collection box is connected to the bottom of the first filter cartridge, and the microplastic collection box is connected to the first filter cartridge, the second filter cartridge, and the third filter cartridge;

[0006] The inner wall of the first filter cartridge is provided with oyster culture mesh plate A, scallop culture mesh plate A, and sea cucumber culture mesh plate A in sequence from top to bottom; the inner wall of the second filter cartridge is provided with oyster culture mesh plate B, scallop culture mesh plate B, and sea cucumber culture mesh plate B in sequence from top to bottom; the interior of the third filter cartridge is provided with oyster culture mesh plate C, scallop culture mesh plate C, and sea cucumber culture mesh plate C in sequence from top to bottom;

[0007] Oysters are placed on the top of the oyster farming net plate A, the oyster farming net plate B and the oyster farming net plate C; scallops are placed on the top of the scallop farming net plate A, the scallop farming net plate B and the scallop farming net plate C; sea cucumbers are placed on the top of the sea cucumber farming net plate A, the sea cucumber farming net plate B and the sea cucumber farming net plate C;

[0008] The first filter cartridge is connected to a first arc-shaped door, the second filter cartridge is connected to a second arc-shaped door, and the third filter cartridge is connected to a third arc-shaped door.

[0009] As a preferred technical solution of the present invention, the first arc door is installed on the first filter cartridge by hinges and snaps, a plurality of first filter holes are evenly arranged on the first filter cartridge and the first arc door, a conical bucket is welded to the bottom of the first filter cartridge, a cross support frame is welded to the top of the conical bucket, and the cross support frame is used to support the second filter cartridge and the third filter cartridge.

[0010] As a preferred technical solution of the present invention, the second arc-shaped door is installed on the second filter cartridge by means of hinges and buckles, and a plurality of second filter holes are evenly arranged on the second arc-shaped door and the second filter cartridge.

[0011] As a preferred technical solution of the present invention, the third arc door is installed on the third filter cylinder through hinges and buckles, and a plurality of third filter holes are evenly arranged on the third arc door and the third filter cylinder. The diameter of the third filter hole is smaller than the diameter of the second filter hole, and the diameter of the second filter hole is smaller than the diameter of the first filter hole.

[0012] As a preferred technical solution of the present invention, a plurality of first through holes are evenly arranged on the oyster farming mesh plate A, the oyster farming mesh plate B and the oyster farming mesh plate C, a plurality of second through holes are evenly arranged on the scallop farming mesh plate A, the scallop farming mesh plate B and the scallop farming mesh plate C, a plurality of third through holes are evenly arranged on the sea cucumber farming mesh plate A, the sea cucumber farming mesh plate B and the sea cucumber farming mesh plate C, the diameter of the first through hole is greater than the diameter of the second through hole, and the diameter of the second through hole is greater than the diameter of the third through hole.

[0013] As a preferred technical solution of the present invention, the tops of the first filter cartridge, the second filter cartridge and the third filter cartridge are all welded with hanging ears, the outer diameter of the second filter cartridge is 5-8mm smaller than the inner diameter of the first plug hole, and the outer diameter of the third filter cartridge is 5-8mm smaller than the inner diameter of the second plug hole.

[0014] As a preferred technical solution of the present invention, a drain pipe is connected to the top of one side of the microplastic collection box, the drain pipe is connected to a water pump, a filter plate is installed inside the microplastic collection box, the bottom of the filter plate is connected to a sedimentation hopper, the bottom of the sedimentation hopper is connected to a sewage pipe, and a valve is installed on the sewage pipe.

[0015] As a preferred technical solution of the present invention, a mounting plate is welded to the bottom of the first filter cartridge, and the mounting plate is fixedly connected to the top of the microplastic collection box by bolts.

[0016] A method for removing microplastics from seawater is implemented using the device of the present invention, and the specific steps are as follows:

[0017] Step 1: Open the third curved door on the third filter cartridge, then place oysters on the top of the oyster culture mesh plate C, place scallops on the top of the scallop culture mesh plate C, place sea cucumbers on the sea cucumber culture mesh plate C, then fix the third curved door with a buckle, and insert the third filter cartridge into the second plug hole of the second filter cartridge;

[0018] Step 2: Then open the second curved door on the second filter cartridge, and then place oysters, scallops and sea cucumbers in the oyster culture mesh plate B, scallop culture mesh plate B and sea cucumber culture mesh plate B in the second filter cartridge in sequence, then fix the second curved door by buckles, and then insert the second filter cartridge into the first plug hole of the third filter cartridge;

[0019] Step 3: Open the first curved door on the first filter cartridge, and then place oysters, scallops and sea cucumbers on the oyster culture mesh plate A, the scallop culture mesh plate A and the sea cucumber culture mesh plate A in the first filter cartridge in sequence, and then fix the first curved door with a buckle or a rope;

[0020] Step 4: Use ropes to thread the lifting ears on the top of the first filter cartridge, the second filter cartridge, and the third filter cartridge, and then lift the first filter cartridge, the second filter cartridge, and the third filter cartridge and place them in the seawater;

[0021] Step 5: Utilize the different mesh diameters on the first filter cartridge, the second filter cartridge, and the third filter cartridge to filter different microplastics, so that the microplastics entering the first filter cartridge are large particles, the microplastics entering the second filter cartridge are medium particles, and the microplastics entering the third filter cartridge are small particles. Use oysters to initially filter and deposit floating microplastics; use scallops for secondary filtration and attachment treatment; use sea cucumbers to promote the deposition and decomposition of microplastics;

[0022] Step 6: The microplastics collected by the filter cartridge are deposited into the conical bucket and enter the microplastic collection box through the conical bucket. Timed collection is adopted. The sewage pipe on the microplastic collection box is connected to the water pump. The water pump is started once at a certain time set by the timer. The duration of each time is 10-20 minutes. Under the action of negative pressure, the microplastics in the first filter cartridge, the second filter cartridge, the third filter cartridge and the microplastics in the sedimentation bucket are sucked into the microplastic collection box. The seawater is filtered through the filter plate and then transported out to realize the circulation filtration of seawater and the collection of microplastics.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention can efficiently remove microplastics in seawater through biological natural filtration and sedimentation functions. Compared with mechanical filtration and chemical treatment methods, the present invention is more environmentally friendly and has no secondary pollution risk;

[0025] 2. The present invention utilizes existing biological populations to treat microplastics, without the need for complex and expensive mechanical equipment and chemical reagents, significantly reducing operating and management costs;

[0026] 3. The device of the present invention adopts a three-layer filtration method to separate the microplastics in seawater into large, medium and small particles, so that the large, medium and small particles of microplastics stay in the corresponding filter cartridges respectively. Each filter cartridge is sequentially provided with oysters, scallops and sea cucumbers from top to bottom to respectively aggregate and treat the large, medium and small particles of microplastics. The treatment with oysters, scallops and sea cucumbers can not only treat the deposited floating microplastics, promote the deposition and decomposition of microplastics, but also prevent the clogging of the filter cartridge filter holes, thereby increasing the service life of the filtration system. There is no need to manually clean the filter holes, thus saving manpower and time.

[0027] 4. The device of the present invention uses a microplastic collection box to collect microplastics settled in the three-layer filter cartridge, as well as microplastics processed by oysters, scallops and sea cucumbers. A water pump is used to form negative pressure to collect the microplastics in the three-layer filter cartridge into the microplastic collection box. The timing collection method is adopted, which not only realizes automatic collection but also saves energy. Oysters, scallops and sea cucumbers are used to process the filtered microplastics of each layer, and then the water pump is used to generate negative pressure to collect the microplastics;

[0028] 5. While purifying microplastics in seawater, the equipment of the present invention can also realize the cultivation of oysters, scallops and sea cucumbers, thereby increasing profits and reducing the cost of seawater purification.

[0029] 6. The method of the present invention can not only realize large-scale seafood farming, but also collect microplastics in seawater and improve the quality of seawater. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the split structure of the second filter cartridge, the first filter cartridge and the third filter cartridge of the present invention;

[0031] Figure 2 This is a schematic diagram of the internal structure of the first filter cartridge of the present invention;

[0032] Figure 3 This is a schematic diagram of the internal structure of the second filter cartridge of the present invention;

[0033] Figure 4 This is a schematic diagram of the internal structure of the third filter cartridge of the present invention;

[0034] Figure 5 This is a schematic diagram of the internal structure of the microplastic collection box of the present invention.

[0035] In the figure: 1. Filter cartridge; 2. Filter cartridge; 3. Filter cartridge; 4. Microplastic collection box; 101. 1. Arc door; 102. 1. Socket; 103. Oyster farming mesh A; 104. Scallop farming mesh A; 105. Sea cucumber farming mesh A; 106. Conical bucket; 107. Cross support frame; 201. 2. Arc door; 202. Oyster farming mesh B; 203. Scallop farming mesh B; 204. Sea cucumber farming mesh B; 205. 2. Socket; 301. 3. Arc door; 302. Oyster farming mesh C; 303. Scallop farming mesh C; 304. Sea cucumber farming mesh C; 401. Filter plate; 402. Drain pipe. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0037] like Figure 1 As shown: The present invention provides an apparatus for removing microplastics from seawater by using a multi-layer biological sedimentation filtration system, comprising a first filter cartridge 1, a second filter cartridge 2, and a third filter cartridge 3, wherein the second filter cartridge 2 is inserted in the middle of the first filter cartridge 1, and the third filter cartridge 3 is inserted in the middle of the second filter cartridge 2, and a microplastic collection box 4 is connected to the bottom of the first filter cartridge 1, and the microplastic collection box 4 is connected to the first filter cartridge 1, the second filter cartridge 2, and the third filter cartridge 3, and the microplastic collection box 4 is used to collect microplastics in the first filter cartridge 1, the second filter cartridge 2, and the third filter cartridge 3;

[0038] like Figure 2-4As shown: the inner wall of the first filter cartridge 1 is provided with oyster culture mesh plates A103, scallop culture mesh plates A104, and sea cucumber culture mesh plates A105 in sequence from top to bottom; the inner wall of the second filter cartridge 2 is provided with oyster culture mesh plates B202, scallop culture mesh plates B203, and sea cucumber culture mesh plates B204 in sequence from top to bottom; the interior of the third filter cartridge 3 is provided with oyster culture mesh plates C302, scallop culture mesh plates C303, and sea cucumber culture mesh plates C304 in sequence from top to bottom;

[0039] Oysters are placed on the top of oyster farming mesh A103, oyster farming mesh B202 and oyster farming mesh C302. The farming water depth is 0-5 meters, and about 100 oysters are placed per square meter for preliminary filtration and deposition of floating microplastics. Oysters have strong filtering ability and are very effective in filtering large microplastics. Scallops are placed on the top of scallop farming mesh A104, scallop farming mesh B203 and scallop farming mesh C303. The farming water depth is 5-15 meters, and about 50 oysters are placed per square meter. Scallops have strong water filtering function and perform secondary filtration and attachment treatment on seawater containing medium-sized microplastic particles. Sea cucumbers are placed on the top of sea cucumber farming mesh A105, sea cucumber farming mesh B204 and sea cucumber farming mesh C304. The farming water depth is 15 meters or less, and about 20 oysters are placed per square meter. Sea cucumbers are used to promote the deposition and decomposition of microplastics. Sea cucumbers can process smaller microplastics in sediments and improve the bottom environment.

[0040] like Figure 2-4 As shown: the first filter cartridge 1 is connected to the first arc door 101 , the second filter cartridge 2 is connected to the second arc door 201 , and the third filter cartridge 3 is connected to the third arc door 301 .

[0041] like Figure 2 As shown: the first arc door 101 is installed on the first filter cartridge 1 by hinges and buckles, and a plurality of first filter holes are evenly arranged on the first filter cartridge 1 and the first arc door 101. A conical bucket 106 is welded to the bottom of the first filter cartridge 1, and a cross support frame 107 is welded to the top of the conical bucket 106. The cross support frame 107 is used to support the second filter cartridge 2 and the third filter cartridge 3 to prevent the second filter cartridge 2 and the third filter cartridge 3 from falling into the microplastic collection box 4. The diameter of the first filter hole is 2-3 cm.

[0042] like Figure 3 As shown: the second arc door 201 is installed on the second filter cartridge 2 through hinges and buckles, and a plurality of second filter holes are evenly arranged on the second arc door 201 and the second filter cartridge 2, and the diameter of the second filter holes is 1.5-2 cm.

[0043] like Figure 4As shown: the third arc door 301 is installed on the third filter cartridge 3 by hinges and buckles, and a number of third filter holes are evenly arranged on the third arc door 301 and the third filter cartridge 3. The diameter of the third filter hole is 0.5-1 cm, and the diameter of the third filter hole is smaller than the diameter of the second filter hole. The diameter of the second filter hole is smaller than the diameter of the first filter hole. Three-layer filtration is adopted to give corresponding biological treatment to large, medium and small particles of microplastics in seawater in a targeted manner, and multi-layer graded filtration can also thoroughly collect microplastics in seawater.

[0044] like Figure 2-4 As shown: a plurality of first through holes are evenly arranged on the oyster farming mesh A103, the oyster farming mesh B202 and the oyster farming mesh C302, a plurality of second through holes are evenly arranged on the scallop farming mesh A104, the scallop farming mesh B203 and the scallop farming mesh C303, a plurality of third through holes are evenly arranged on the sea cucumber farming mesh A105, the sea cucumber farming mesh B204 and the sea cucumber farming mesh C304, the diameter of the first through hole is greater than the diameter of the second through hole, the diameter of the second through hole is greater than the diameter of the third through hole, and through holes of different diameters are arranged to adapt to the life of oysters, scallops and sea cucumbers.

[0045] like Figure 1 As shown: the tops of the first filter cartridge 1, the second filter cartridge 2 and the third filter cartridge 3 are all welded with hanging ears, the outer diameter of the second filter cartridge 2 is 5-8mm smaller than the inner diameter of the first plug hole 102, and the outer diameter of the third filter cartridge 3 is 5-8mm smaller than the inner diameter of the second plug hole 205, so that the third filter cartridge 3 can be quickly inserted into the second filter cartridge 2, and the second filter cartridge 2 can be quickly inserted into the first filter cartridge 1.

[0046] like Figure 5 As shown: a drain pipe 402 is connected to the top of one side of the microplastic collection box 4, and the drain pipe 402 is connected to a water pump. When the water pump is working, negative pressure is generated in the microplastic collection box 4, thereby absorbing the microplastics in the sedimentation bucket 403, the first filter cartridge 1, the second filter cartridge 2 and the third filter cartridge 3. A filter plate 401 is installed inside the microplastic collection box 4, and the filter plate 401 is used to filter the microplastics in the microplastic collection box 4, so that the seawater is discharged to prevent the microplastics from polluting the seawater again. A sedimentation bucket 403 is connected to the bottom of the filter plate 401, and a sewage pipe 404 is connected to the bottom of the sedimentation bucket 403. A valve 405 is installed on the sewage pipe 404. The valve 405 can be an electric valve or a manual valve, which is used to discharge the microplastics in the microplastic collection box 4 from the sewage pipe 404.

[0047] A mounting plate is welded to the bottom of the first filter cartridge 1 , and the mounting plate is fixedly connected to the top of the microplastic collection box 4 by bolts, so assembly and disassembly is very simple and convenient.

[0048] A method for removing microplastics from seawater is implemented using the device of the present invention, and the specific steps are as follows:

[0049] Step 1: Open the third curved door 301 on the third filter cartridge 3, then place oysters on the top of the oyster culture mesh plate C302, place scallops on the top of the scallop culture mesh plate C303, place sea cucumbers on the sea cucumber culture mesh plate C304, then fix the third curved door 301 by snapping, and insert the third filter cartridge 3 into the second insertion hole 205 of the second filter cartridge 2;

[0050] Step 2: Then open the second curved door 201 on the second filter cartridge 2, and then place oysters, scallops and sea cucumbers in the oyster culture mesh plate B202, scallop culture mesh plate B203 and sea cucumber culture mesh plate B204 in the second filter cartridge 2 in sequence, then fix the second curved door 201 by buckles, and then insert the second filter cartridge 2 into the first insertion hole 102 of the third filter cartridge 3;

[0051] Step 3: Open the first curved door 101 on the first filter cartridge 1, and then place oysters, scallops and sea cucumbers on the oyster culture mesh A103, scallop culture mesh A104 and sea cucumber culture mesh A105 in the first filter cartridge 1 in sequence, and then fix the first curved door 101 by buckles or ropes;

[0052] Step 4: Use ropes to thread the lifting ears on the top of the first filter cartridge 1, the second filter cartridge 2, and the third filter cartridge 3, and then lift the first filter cartridge 1, the second filter cartridge 2, and the third filter cartridge 3 and place them in seawater;

[0053] Step 5: Different mesh diameters on the first filter cartridge 1, the second filter cartridge 2, and the third filter cartridge 3 are used to filter different microplastics, so that the microplastics entering the first filter cartridge 1 are large particles, the microplastics entering the second filter cartridge 2 are medium particles, and the microplastics entering the third filter cartridge 3 are small particles. Oysters are used to initially filter and deposit floating microplastics; scallops are used for secondary filtration and attachment treatment; and sea cucumbers are used to promote the deposition and decomposition of microplastics;

[0054] Step 6: The microplastics collected by the filter cartridge are deposited into the conical bucket 106, and enter the microplastic collection box 4 through the conical bucket 106. Timed collection is adopted, and the sewage pipe 404 on the microplastic collection box 4 is connected to the water pump. The water pump is started once at a certain time set by the timer, and the duration of each time is 10-20 minutes. Under the action of negative pressure, the microplastics in the first filter cartridge 1, the second filter cartridge 2, and the third filter cartridge 3 and the microplastics in the sedimentation bucket 403 are sucked into the microplastic collection box 4. The seawater is filtered through the filter plate 401 and then transported out to realize the circulation filtration of seawater and the collection of microplastics.

[0055] Example 1: Haizhou Bay is part of the Lianyungang waters, located in the northern coast of Jiangsu Province. It has become an important marine aquaculture area due to its unique geographical and natural conditions. With the increase of human activities and aquaculture devices, microplastics in the environment are also increasing, accumulating in organisms and eventually entering the human body through the food chain. The present invention sets up a total of 12 survey stations in the aquaculture area and non-aquaculture area in the eastern sea area of ​​Lianyun District, Lianyungang City, Jiangsu Province, denoted as S1~S12. The sampling time period is three months in total, with an interval of one month, and surface water samples are collected separately.

[0056] Each station was sampled three times in parallel, and the samples collected on site were passed through 5.0mm and 0.1mm stainless steel layered mesh sieves in turn. The intercepted materials on the 5.0mm mesh were retained according to the monitoring purpose; the glass sample bottle was rinsed with an appropriate amount of pure water so that all samples were transferred to the mesh, and the above operation was repeated three times; the mesh was rinsed with an appropriate amount of pure water, and all the intercepted materials on the 0.1mm mesh were transferred to a 500mL beaker, and the beaker was placed in an oven at 60°C for drying. Digestion treatment uses wet peroxide oxidation method to eliminate organic interference in the sample. Digestion treatment is carried out according to the following steps: After the sample is dried, add 20mL of 0.05mol / L divalent iron solution to the beaker, and then add 20mL of 30% hydrogen peroxide solution, and cover the mouth of the beaker with a watch glass or aluminum foil; leave it at room temperature for about 10 minutes. If the reaction is violent, immediately put it in a cold water bath; if organic matter can still be observed, add another 20mL of 30% hydrogen peroxide solution to continue digestion, and repeat the above steps until the organic matter is completely digested. Density separation is carried out to separate microplastics from digestion residues as follows: Add 6g of sodium chloride to every 20mL of the above mixed solution. After the sodium chloride is completely dissolved, transfer the mixed solution to the flotation device. Use 1.2g / cm 3 Rinse the beaker with sodium chloride to transfer all solid matter to the flotation device and let it stand overnight; observe with the naked eye whether there is solid matter settling at the bottom of the funnel, control the flow rate, let the sediment flow out slowly, pick out the suspected plastic sample with tweezers, and discard other non-plastic sediments; filter the supernatant using a glass fiber filter membrane dried to constant weight, rinse the funnel with pure water several times, transfer all the samples to the filter membrane, remove the filter membrane and place it in a clean glass culture dish, dry it at 60℃ or dry it naturally. Analyze and identify the stored solid sediment and the substances intercepted on the filter membrane. The statistical results are shown in Table 1.

[0057] Table 1: Distribution of microplastics in water

[0058]

[0059]

[0060] From the experimental results, it can be seen that the abundance of microplastics in the water bodies of the three aquaculture areas of oyster farming, scallop farming and sea cucumber farming has gradually decreased with time, and the abundance of microplastics in the aquaculture areas of oyster farming, scallop farming and sea cucumber farming has gradually approached or even been lower than the abundance of microplastics in the water bodies of non-farming areas. The natural filtration and sedimentation functions of cage-cultured organisms can be used to efficiently remove microplastic particles in seawater in actual situations. This method is practical and feasible.

[0061] Example 2: A total of 268 biological samples of oysters, scallops, and sea cucumbers were collected from the Haizhou Bay aquaculture area in Lianyungang, Jiangsu. The collected samples were wrapped in aluminum foil and placed in a sealed bag. The individual sizes should be as consistent as possible and placed in a -4°C incubator for analysis and testing. The surface was washed with pure water and drained. The samples were placed on a tray after draining. The shellfish were inserted with dissecting tools to pry open the shell seams. The adductor muscles on both sides were cut off close to the inner wall of the shell with a scalpel. The soft tissue was removed with tweezers, and the soft tissue was separated and the relevant biological characteristics were recorded. The tissue sample was placed in a beaker, which was placed in a fume hood. 10 mL of potassium hydroxide solution was added for every 1 g of wet sample, and the beaker mouth was covered with aluminum foil or a watch glass; the beaker was placed in a 60°C water bath until the sample was completely digested. Pass the digested solution through a 100μm stainless steel mesh while hot, rinse the inner wall of the beaker with 60℃ pure water, transfer all samples to the mesh, and repeat three times; rinse the mesh with a large amount of pure water to intercept the sample and remove the alkaline solution; rinse the mesh with pure water, transfer all the intercepted materials on the mesh to a 500mL beaker, add 36g of sodium iodide to every 20mL of the above solution, stir and dissolve; transfer the solution in the beaker to the flotation device, rinse the beaker with sodium iodide solution several times, transfer all the samples in the beaker to the flotation device, and let it stand overnight; observe whether there is solid sedimentation at the bottom of the funnel. Control the flow rate so that the sediment flows out slowly. Use tweezers to pick out suspected plastic samples and discard other non-plastic component sediments; filter the supernatant with a glass fiber filter membrane. Rinse the funnel with pure water several times to transfer all the samples to the filter membrane. Remove the filter membrane and place it in a clean glass culture dish and dry it at 60℃. Finally, observe and analyze the microplastics on the filter membrane using a stereo microscope. The statistical results are shown in Table 2.

[0062] Table 2: Biological characteristics of organisms and distribution of microplastics

[0063]

[0064]

[0065] The experimental results show that microplastics are found in all organisms in the three aquaculture areas of oyster farming, scallop farming, and sea cucumber farming, with a detection rate of 100%. In addition, the abundance of microplastics in farmed oysters is higher than that in farmed scallops and higher than that in farmed sea cucumbers. This method has the potential to efficiently remove microplastic particles from seawater by quantifying the amount of microplastics in farmed organisms and enabling the natural filtration and biological sedimentation functions of caged cultured organisms.

[0066] Example 3: Oysters, scallops, and sea cucumbers were selected for testing in aquaculture cages. A controlled sea area with uniform water conditions was selected in Haizhou Bay, Lianyungang. The test period was twenty days. Before starting the test, the initial microplastic concentration in the water was measured, and at the end of the test, the microplastic concentration in the water was measured again. In order to carry out effective monitoring and data collection. Different numbers of aquaculture combination test groups and one or more control groups were set up to design multiple combinations for comparison. 50L of water samples and 400g of biological sediment samples were collected regularly to analyze the concentration and type of microplastics. Analyze the effects of different ratios on the removal efficiency of microplastics.

[0067] The extraction of microplastics from water bodies was the same as in Example 1. After the biological sediment sample was mixed, 10 g was weighed and the water content (WH2O) was determined according to the method in Chapter 19 of GB17378.5-2007; 200 g of sediment sample (m1) was weighed and transferred to a 500 mL beaker for standby use, and three parallels were made. The initial flotation of the sample was carried out according to the following steps: add 1.8g / mL sodium iodide solution to the 500mL mark of the beaker, stir thoroughly, and make the plastic sample float on the surface of the solution; let it stand until the solution is clear, collect the supernatant, add sodium iodide solution to the beaker containing the sample again, and repeat the flotation process until there is no suspected plastic sample floating on the liquid surface; combine the supernatant, and pass the supernatant through stainless steel sieves with pore sizes of 5.0mm and 0.1mm in turn; use an appropriate amount of pure water to rinse the material trapped on the 0.1mm sieve and transfer it to a 500mL beaker; cover the beaker with aluminum foil but not seal it, and place it in a constant temperature drying oven (60℃) to dry. Digestion of biological organic matter was carried out according to the following steps: after the sample was dried, add 20mL of 0.05mol / L divalent iron solution to the beaker in a fume hood, then add 20mL of 30% hydrogen peroxide solution, cover the beaker mouth with aluminum foil, and place it at room temperature until no obvious bubbles are generated. If the organic matter is not completely digested, add 20mL of 30% hydrogen peroxide solution to continue digestion, and repeat the above operation until the digestion is complete. After the organic matter is completely digested, if there are more shells remaining, add 20mL of 4.5% hydrochloric acid to continue digestion until no visible shells remain. If there are fewer shell impurities in the sediment and it does not affect the analysis and detection, hydrochloric acid digestion can be omitted. Pass the mixed solution through a 0.1mm sieve, rinse the material retained on the sieve with an appropriate amount of pure water, and transfer it to a 500mL beaker. Transfer the supernatant to a glass fiber filter membrane for filtration. Rinse the beaker with pure water several times to transfer all the samples to the filter membrane. Remove the filter membrane and place it in a clean glass culture dish, dry it at 60℃ or dry it naturally. Analyze and identify the preserved solid sediment and the material retained on the filter membrane. Finally, observe and analyze the microplastics on the filter membrane using a stereo microscope. The statistical results are shown in Table 3.

[0068] Table 3: Statistics of aquaculture combination test and microplastic recovery results

[0069]

[0070]

[0071] The statistical results show that the overall impact of biological combinations on the dynamic distribution of microplastic removal rates in water bodies was analyzed by combining the change data of the initial concentration of microplastics in water bodies. It was found that the removal rates of microplastics in water bodies were different in the different biological ratio combinations of single oyster group, single scallop group, single sea cucumber group, oyster + scallop group, oyster + scallop + sea cucumber group. In the designed combination, it was found that the removal rate of microplastics in water bodies was significantly improved in the combination of 100 oysters + 50 scallops + 20 sea cucumbers. This method can effectively remove seawater microplastics in aquaculture environments.

[0072] The above embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A device for removing microplastics from seawater using a multi-layer biological sedimentation filtration system, comprising a first filter cartridge (1), a second filter cartridge (2), and a third filter cartridge (3), characterized in that: The second filter cartridge (2) is inserted into the middle of the first filter cartridge (1), the third filter cartridge (3) is inserted into the middle of the second filter cartridge (2), the bottom of the first filter cartridge (1) is connected to a microplastic collection box (4), and the microplastic collection box (4) is in communication with the first filter cartridge (1), the second filter cartridge (2) and the third filter cartridge (3); The inner wall of the first filter cartridge (1) is provided with oyster culture mesh panels A (103), scallop culture mesh panels A (104), and sea cucumber culture mesh panels A (105) in sequence from top to bottom; the inner wall of the second filter cartridge (2) is provided with oyster culture mesh panels B (202), scallop culture mesh panels B (203), and sea cucumber culture mesh panels B (204) in sequence from top to bottom; the interior of the third filter cartridge (3) is provided with oyster culture mesh panels C (302), scallop culture mesh panels C (303), and sea cucumber culture mesh panels C (304) in sequence from top to bottom; Oysters are placed on the top of the oyster culture mesh plate A (103), the oyster culture mesh plate B (202) and the oyster culture mesh plate C (302); scallops are placed on the top of the scallop culture mesh plate A (104), the scallop culture mesh plate B (203) and the scallop culture mesh plate C (303); sea cucumbers are placed on the top of the sea cucumber culture mesh plate A (105), the sea cucumber culture mesh plate B (204) and the sea cucumber culture mesh plate C (304); The first filter cartridge (1) is connected to a first arc-shaped door (101), the second filter cartridge (2) is connected to a second arc-shaped door (201), and the third filter cartridge (3) is connected to a third arc-shaped door (301).

2. The device for removing microplastics from seawater using a multi-layer biological sedimentation filtration system according to claim 1, characterized in that: The first arc-shaped door (101) is mounted on the first filter cartridge (1) via hinges and snaps; a plurality of first filter holes are evenly arranged on the first filter cartridge (1) and the first arc-shaped door (101); a conical bucket (106) is welded to the bottom of the first filter cartridge (1); a cross support frame (107) is welded to the top of the conical bucket (106); the cross support frame (107) is used to support the second filter cartridge (2) and the third filter cartridge (3).

3. The device for removing microplastics from seawater using a multi-layer biological sedimentation filtration system according to claim 2, characterized in that: The second arc-shaped door (201) is mounted on the second filter cartridge (2) via hinges and buckles, and a plurality of second filter holes are evenly arranged on the second arc-shaped door (201) and the second filter cartridge (2).

4. The device for removing microplastics from seawater using a multi-layer biological sedimentation filtration system according to claim 3, characterized in that: The third arc-shaped door (301) is mounted on the third filter cartridge (3) via hinges and buckles; a plurality of third filter holes are evenly arranged on the third arc-shaped door (301) and the third filter cartridge (3); the diameter of the third filter hole is smaller than the diameter of the second filter hole, and the diameter of the second filter hole is smaller than the diameter of the first filter hole.

5. The device for removing microplastics from seawater using a multi-layer biological sedimentation filtration system according to claim 1, characterized in that: A plurality of first through holes are evenly arranged on the oyster farming mesh plate A (103), the oyster farming mesh plate B (202) and the oyster farming mesh plate C (302); a plurality of second through holes are evenly arranged on the scallop farming mesh plate A (104), the scallop farming mesh plate B (203) and the scallop farming mesh plate C (303); a plurality of third through holes are evenly arranged on the sea cucumber farming mesh plate A (105), the sea cucumber farming mesh plate B (204) and the sea cucumber farming mesh plate C (304); the diameter of the first through hole is greater than the diameter of the second through hole, and the diameter of the second through hole is greater than the diameter of the third through hole.

6. The device for removing microplastics from seawater using a multi-layer biological sedimentation filtration system according to claim 1, characterized in that: The tops of the first filter cartridge (1), the second filter cartridge (2) and the third filter cartridge (3) are all welded with hanging ears, the outer diameter of the second filter cartridge (2) is 5-8 mm smaller than the inner diameter of the first plug hole (102), and the outer diameter of the third filter cartridge (3) is 5-8 mm smaller than the inner diameter of the second plug hole (205).

7. The device for removing microplastics from seawater using a multi-layer biological sedimentation filtration system according to claim 1, characterized in that: A drainage pipe (402) is connected to the top of one side of the microplastic collection box (4), and the drainage pipe (402) is connected to a water pump. A filter plate (401) is installed inside the microplastic collection box (4), and a sedimentation hopper (403) is connected to the bottom of the filter plate (401), and a sewage pipe (404) is connected to the bottom of the sedimentation hopper (403), and a valve (405) is installed on the sewage pipe (404).

8. The device for removing microplastics from seawater using a multi-layer biological sedimentation filtration system according to claim 1, characterized in that: A mounting plate is welded to the bottom of the first filter cartridge (1), and the mounting plate is fixedly connected to the top of the microplastic collection box (4) by means of bolts.

9. A method for removing microplastics from seawater, characterized in that: The method is implemented by using the device described in any one of claims 1 to 8, and the specific steps are as follows: Step 1: Open the third curved door (301) on the third filter cartridge (3), then place oysters on the top of the oyster culture mesh plate C (302), place scallops on the top of the scallop culture mesh plate C (303), place sea cucumbers on the sea cucumber culture mesh plate C (304), then fix the third curved door (301) by snapping, and insert the third filter cartridge (3) into the second insertion hole (205) of the second filter cartridge (2); Step 2: then open the second curved door (201) on the second filter cartridge (2), then place oysters, scallops and sea cucumbers on the oyster culture mesh plate B (202), scallop culture mesh plate B (203) and sea cucumber culture mesh plate B (204) in the second filter cartridge (2) in sequence, then fix the second curved door (201) by means of a buckle, and then insert the second filter cartridge (2) into the first insertion hole (102) of the third filter cartridge (3); Step 3: Open the first curved door (101) on the first filter cartridge (1), then place oysters, scallops and sea cucumbers on the oyster culture mesh plate A (103), the scallop culture mesh plate A (104) and the sea cucumber culture mesh plate A (105) in the first filter cartridge (1) in sequence, and then fix the first curved door (101) by means of buckles or ropes; Step 4: Use ropes to thread the lifting ears at the top of the first filter cartridge (1), the second filter cartridge (2), and the third filter cartridge (3), and then lift the first filter cartridge (1), the second filter cartridge (2), and the third filter cartridge (3) and place them in seawater; Step 5: Using the different mesh diameters on the first filter cartridge (1), the second filter cartridge (2), and the third filter cartridge (3), different microplastics are filtered, so that the microplastics entering the first filter cartridge (1) are large particles, the microplastics entering the second filter cartridge (2) are medium particles, and the microplastics entering the third filter cartridge (3) are small particles. Oysters are used to initially filter and deposit floating microplastics; scallops are used for secondary filtration and attachment treatment; Using sea cucumbers to promote the deposition and decomposition of microplastics; Step 6: The microplastics collected by the filter cartridge are deposited into the conical bucket (106), and enter the microplastic collection box (4) through the conical bucket (106). Timed collection is adopted, and the sewage pipe (404) on the microplastic collection box (4) is connected to a water pump. The water pump is started once at a certain time set by a timer, and the duration of each time is 10-20 minutes. Under the action of negative pressure, the microplastics in the first filter cartridge (1), the second filter cartridge (2), and the third filter cartridge (3) and the microplastics in the sedimentation bucket (403) are sucked into the microplastic collection box (4), and the seawater is filtered through the filter plate (401) and then transported out, so as to realize the circulation filtration of seawater and collect the microplastics.

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